- Jun 08, 2015
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Ingo Molnar authored
Make the 32-bit syscall entry code a bit more readable: - use consistent assembly coding style similar to entry_64.S - remove old comments that are not true anymore - eliminate whitespace noise - use consistent vertical spacing - fix various comments No code changed: # arch/x86/entry/entry_32.o: text data bss dec hex filename 6025 0 0 6025 1789 entry_32.o.before 6025 0 0 6025 1789 entry_32.o.after md5: f3fa16b2b0dca804f052deb6b30ba6cb entry_32.o.before.asm f3fa16b2b0dca804f052deb6b30ba6cb entry_32.o.after.asm Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
The 'system_call' entry points differ starkly between native 32-bit and 64-bit kernels: on 32-bit kernels it defines the INT 0x80 entry point, while on 64-bit it's the SYSCALL entry point. This is pretty confusing when looking at generic code, and it also obscures the nature of the entry point at the assembly level. So unangle this by splitting the name into its two uses: system_call (32) -> entry_INT80_32 system_call (64) -> entry_SYSCALL_64 As per the generic naming scheme for x86 system call entry points: entry_MNEMONIC_qualifier where 'qualifier' is one of _32, _64 or _compat. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
x86/asm/entry: Untangle 'ia32_sysenter_target' into two entry points: entry_SYSENTER_32 and entry_SYSENTER_compat So the SYSENTER instruction is pretty quirky and it has different behavior depending on bitness and CPU maker. Yet we create a false sense of coherency by naming it 'ia32_sysenter_target' in both of the cases. Split the name into its two uses: ia32_sysenter_target (32) -> entry_SYSENTER_32 ia32_sysenter_target (64) -> entry_SYSENTER_compat As per the generic naming scheme for x86 system call entry points: entry_MNEMONIC_qualifier where 'qualifier' is one of _32, _64 or _compat. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
Rename the following system call entry points: ia32_cstar_target -> entry_SYSCALL_compat ia32_syscall -> entry_INT80_compat The generic naming scheme for x86 system call entry points is: entry_MNEMONIC_qualifier where 'qualifier' is one of _32, _64 or _compat. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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- Jun 07, 2015
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Ingo Molnar authored
So we now have the following system entry code related files, which define the following system call instruction and other entry paths: entry_32.S # 32-bit binaries on 32-bit kernels entry_64.S # 64-bit binaries on 64-bit kernels entry_64_compat.S # 32-bit binaries on 64-bit kernels Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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- Jun 05, 2015
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Denys Vlasenko authored
Really swap arguments #4 and #5 in stub32_clone instead of "optimizing" it into a move. Yes, tls_val is currently unused. Yes, on some CPUs XCHG is a little bit more expensive than MOV. But a cycle or two on an expensive syscall like clone() is way below noise floor, and this optimization is simply not worth the obfuscation of logic. [ There's also ongoing work on the clone() ABI by Josh Triplett that will depend on this change later on. ] Signed-off-by:
Denys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1433339930-20880-2-git-send-email-dvlasenk@redhat.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Denys Vlasenko authored
The reason for copying of %r8 to %rcx is quite non-obvious. Add a comment which explains why it is done. Signed-off-by:
Denys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1433339930-20880-1-git-send-email-dvlasenk@redhat.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
Make the 64-bit compat 32-bit syscall entry code a bit more readable: - eliminate whitespace noise - use consistent vertical spacing - use consistent assembly coding style similar to entry_64.S - fix various comments No code changed: arch/x86/entry/ia32entry.o: text data bss dec hex filename 1391 0 0 1391 56f ia32entry.o.before 1391 0 0 1391 56f ia32entry.o.after md5: f28501dcc366e68b557313942c6496d6 ia32entry.o.before.asm f28501dcc366e68b557313942c6496d6 ia32entry.o.after.asm Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Denys Vlasenko authored
SYSENTER and SYSCALL 32-bit entry points differ in handling of arg2 and arg6. SYSENTER: * ecx arg2 * ebp user stack * 0(%ebp) arg6 SYSCALL: * ebp arg2 * esp user stack * 0(%esp) arg6 Sysenter code loads 0(%ebp) to %ebp right away. (This destroys %ebp. It means we do not preserve it on return. It's not causing problems since userspace VDSO code does not depend on it, and SYSENTER insn can't be sanely used outside of VDSO). Syscall code loads 0(%ebp) to %r9. This allows to eliminate one MOV insn (r9 is a register where arg6 should be for 64-bit ABI), but on audit/ptrace code paths this requires juggling of r9 and ebp: (1) ptrace expects arg6 to be in pt_regs->bp; (2) r9 is callee-clobbered register and needs to be saved/restored around calls to C functions. This patch changes syscall code to load 0(%ebp) to %ebp, making it more similar to sysenter code. It's a bit smaller: text data bss dec hex filename 1407 0 0 1407 57f ia32entry.o.before 1391 0 0 1391 56f ia32entry.o To preserve ABI compat, we restore ebp on exit. Run-tested. Signed-off-by:
Denys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1433336169-18964-1-git-send-email-dvlasenk@redhat.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Denys Vlasenko authored
This macro is small, has only three callsites, and one of them is slightly different using a conditional parameter. A few saved lines aren't worth the resulting obfuscation. Generated machine code is identical. Signed-off-by:
Denys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1433271842-9139-2-git-send-email-dvlasenk@redhat.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Denys Vlasenko authored
This macro is small, has only four callsites, and one of them is slightly different using a conditional parameter. A few saved lines aren't worth the resulting obfuscation. Generated machine code is identical. Signed-off-by:
Denys Vlasenko <dvlasenk@redhat.com> [ Added comments. ] Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1433271842-9139-1-git-send-email-dvlasenk@redhat.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Denys Vlasenko authored
32-bit syscall entry points do not save the complete pt_regs struct, they leave some fields uninitialized. However, they must be careful to not leak uninitialized data in pt_regs->r8..r11 to ptrace users. CLEAR_RREGS macro is used to zero these fields out when needed. However, in the int80 code path this zeroing is unconditional. This patch simplifies it by storing zeroes there right away, when pt_regs is constructed on stack. This uses shorter instructions: text data bss dec hex filename 1423 0 0 1423 58f ia32entry.o.before 1407 0 0 1407 57f ia32entry.o Compile-tested. Signed-off-by:
Denys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1433266510-2938-1-git-send-email-dvlasenk@redhat.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Andy Lutomirski authored
INTERRUPT_RETURN turns into a jmp instruction. There's no need for extra indirection. Signed-off-by:
Andy Lutomirski <luto@kernel.org> Cc: <linux-kernel@vger.kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/2f2318653dbad284a59311f13f08cea71298fd7c.1433449436.git.luto@kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Andy Lutomirski authored
The wrmsrl_safe macro performs invalid shifts if the value argument is 32 bits. This makes it unnecessarily awkward to write code that puts an unsigned long into an MSR. Convert it to a real inline function. For inspiration, see: 7c74d5b7 ("x86/asm/entry/64: Fix MSR_IA32_SYSENTER_CS MSR value"). Signed-off-by:
Andy Lutomirski <luto@kernel.org> Cc: <linux-kernel@vger.kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> [ Applied small improvements. ] Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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- Jun 04, 2015
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Ingo Molnar authored
The vsyscall code is entry code too, so move it to arch/x86/entry/vsyscall/. Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
The build time generated syscall definitions are entry code related, move them into the arch/x86/entry/ directory. Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
asm/calling.h is private to the entry code, make this more apparent by moving it to the new arch/x86/entry/ directory. Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
These are all calling x86 entry code functions, so move them close to other entry code. Change lib-y to obj-y: there's no real difference between the two as we don't really drop any of them during the linking stage, and obj-y is the more common approach for core kernel object code. Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
Move the ia32entry.S file over into arch/x86/entry/. Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
Create a new directory hierarchy for the low level x86 entry code: arch/x86/entry/* This will host all the low level glue that is currently scattered all across arch/x86/. Start with entry_64.S and entry_32.S. Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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- Jun 02, 2015
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Jan Beulich authored
retint_kernel doesn't require %rcx to be pointing to thread info (anymore?), and the code on the two alternative paths is - not really surprisingly - identical. Signed-off-by:
Jan Beulich <jbeulich@suse.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/556C664F020000780007FB64@mail.emea.novell.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Jan Beulich authored
Doing so allows adjustments by 128 bytes (occurring for REMOVE_PT_GPREGS_FROM_STACK 8 uses) to be expressed with a single byte immediate. Signed-off-by:
Jan Beulich <jbeulich@suse.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/556C660F020000780007FB60@mail.emea.novell.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
So the dwarf2 annotations in low level assembly code have become an increasing hindrance: unreadable, messy macros mixed into some of the most security sensitive code paths of the Linux kernel. These debug info annotations don't even buy the upstream kernel anything: dwarf driven stack unwinding has caused problems in the past so it's out of tree, and the upstream kernel only uses the much more robust framepointers based stack unwinding method. In addition to that there's a steady, slow bitrot going on with these annotations, requiring frequent fixups. There's no tooling and no functionality upstream that keeps it correct. So burn down the sick forest, allowing new, healthier growth: 27 files changed, 350 insertions(+), 1101 deletions(-) Someone who has the willingness and time to do this properly can attempt to reintroduce dwarf debuginfo in x86 assembly code plus dwarf unwinding from first principles, with the following conditions: - it should be maximally readable, and maximally low-key to 'ordinary' code reading and maintenance. - find a build time method to insert dwarf annotations automatically in the most common cases, for pop/push instructions that manipulate the stack pointer. This could be done for example via a preprocessing step that just looks for common patterns - plus special annotations for the few cases where we want to depart from the default. We have hundreds of CFI annotations, so automating most of that makes sense. - it should come with build tooling checks that ensure that CFI annotations are sensible. We've seen such efforts from the framepointer side, and there's no reason it couldn't be done on the dwarf side. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frédéric Weisbecker <fweisbec@gmail.com Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jan Beulich <JBeulich@suse.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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- May 24, 2015
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Andy Lutomirski authored
The early_idt_handlers asm code generates an array of entry points spaced nine bytes apart. It's not really clear from that code or from the places that reference it what's going on, and the code only works in the first place because GAS never generates two-byte JMP instructions when jumping to global labels. Clean up the code to generate the correct array stride (member size) explicitly. This should be considerably more robust against screw-ups, as GAS will warn if a .fill directive has a negative count. Using '. =' to advance would have been even more robust (it would generate an actual error if it tried to move backwards), but it would pad with nulls, confusing anyone who tries to disassemble the code. The new scheme should be much clearer to future readers. While we're at it, improve the comments and rename the array and common code. Binutils may start relaxing jumps to non-weak labels. If so, this change will fix our build, and we may need to backport this change. Before, on x86_64: 0000000000000000 <early_idt_handlers>: 0: 6a 00 pushq $0x0 2: 6a 00 pushq $0x0 4: e9 00 00 00 00 jmpq 9 <early_idt_handlers+0x9> 5: R_X86_64_PC32 early_idt_handler-0x4 ... 48: 66 90 xchg %ax,%ax 4a: 6a 08 pushq $0x8 4c: e9 00 00 00 00 jmpq 51 <early_idt_handlers+0x51> 4d: R_X86_64_PC32 early_idt_handler-0x4 ... 117: 6a 00 pushq $0x0 119: 6a 1f pushq $0x1f 11b: e9 00 00 00 00 jmpq 120 <early_idt_handler> 11c: R_X86_64_PC32 early_idt_handler-0x4 After: 0000000000000000 <early_idt_handler_array>: 0: 6a 00 pushq $0x0 2: 6a 00 pushq $0x0 4: e9 14 01 00 00 jmpq 11d <early_idt_handler_common> ... 48: 6a 08 pushq $0x8 4a: e9 d1 00 00 00 jmpq 120 <early_idt_handler_common> 4f: cc int3 50: cc int3 ... 117: 6a 00 pushq $0x0 119: 6a 1f pushq $0x1f 11b: eb 03 jmp 120 <early_idt_handler_common> 11d: cc int3 11e: cc int3 11f: cc int3 Signed-off-by:
Andy Lutomirski <luto@kernel.org> Acked-by:
H. Peter Anvin <hpa@linux.intel.com> Cc: Binutils <binutils@sourceware.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H.J. Lu <hjl.tools@gmail.com> Cc: Jan Beulich <JBeulich@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/ac027962af343b0c599cbfcf50b945ad2ef3d7a8.1432336324.git.luto@kernel.org Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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- May 17, 2015
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Denys Vlasenko authored
The "movw %ds,%cx" instruction needs a 0x66 prefix, while "movl %ds,%ecx" does not. The difference is that latter form (on 64-bit CPUs) overwrites the entire %ecx, not only its lower half. But subsequent code doesn't depend on the value of upper half of %ecx, so we can safely use the shorter instruction. The new code is also faster than the old one - now we don't depend on the old value of %ecx, but this code fragment is not performance-critical so it does not matter much. Signed-off-by:
Denys Vlasenko <dvlasenk@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Drewry <wad@chromium.org> Link: http://lkml.kernel.org/r/1431722346-26585-1-git-send-email-dvlasenk@redhat.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Borislav Petkov authored
Make the disassembly look less confusing: -- head_64.o.before.asm ++ head_64.o.after.asm 0000000000000120 <early_idt_handler>: 120: fc cld 121: 83 3c 24 02 cmpl $0x2,(%rsp) - 125: 0f 84 9d 00 00 00 je 1c8 <is_nmi> + 125: 0f 84 9d 00 00 00 je 1c8 <early_idt_handler+0xa8> 12b: 83 3d 00 00 00 00 02 cmpl $0x2,0x0(%rip) # 132 <early_idt_handler+0x12> 132: 74 7e je 1b2 <early_idt_handler+0x92> 134: ff 05 00 00 00 00 incl 0x0(%rip) # 13a <early_idt_handler+0x1a> @@ -1198,9 +1198,7 @@ Disassembly of section .init.text: 1bf: 5a pop %rdx 1c0: 59 pop %rcx 1c1: 58 pop %rax - 1c2: ff 0d 00 00 00 00 decl 0x0(%rip) # 1c8 <is_nmi> - -00000000000001c8 <is_nmi>: + 1c2: ff 0d 00 00 00 00 decl 0x0(%rip) # 1c8 <early_idt_handler+0xa8> 1c8: 48 83 c4 10 add $0x10,%rsp 1cc: 48 cf iretq -- head_32.o.before.asm ++ head_32.o.after.asm 0000016c <early_idt_handler>: 16c: fc cld 16d: 83 3c 24 02 cmpl $0x2,(%esp) - 171: 74 73 je 1e6 <is_nmi> + 171: 74 73 je 1e6 <ex_entry+0xc> 173: 36 83 3d 00 00 00 00 cmpl $0x2,%ss:0x0 17a: 02 17b: 74 5a je 1d7 <hlt_loop> @@ -483,8 +483,6 @@ Disassembly of section .init.text: 1dd: 59 pop %ecx 1de: 58 pop %eax 1df: 36 ff 0d 00 00 00 00 decl %ss:0x0 - -000001e6 <is_nmi>: 1e6: 83 c4 08 add $0x8,%esp 1e9: cf iret 1ea: 66 90 xchg %ax,%ax No functionality change. Signed-off-by:
Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431793079-11153-1-git-send-email-bp@alien8.de Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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Ingo Molnar authored
Conflicts: tools/testing/selftests/x86/Makefile tools/testing/selftests/x86/run_x86_tests.sh
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Ingo Molnar authored
Packing loops tightly (-falign-loops=1) is beneficial to code size: text data bss dec filename 12566391 1617840 1089536 15273767 vmlinux.align.16-byte 12224951 1617840 1089536 14932327 vmlinux.align.1-byte 11976567 1617840 1089536 14683943 vmlinux.align.1-byte.funcs-1-byte 11903735 1617840 1089536 14611111 vmlinux.align.1-byte.funcs-1-byte.loops-1-byte Which reduces the size of the kernel by another 0.6%, so the the total combined size reduction of the alignment-packing patches is ~5.5%. The x86 decoder bandwidth and caching arguments laid out in: be6cb027 ("x86: Align jump targets to 1-byte boundaries") apply to loop alignment as well. Furtermore, modern CPU uarchs have a loop cache/buffer that is a L0 cache before even any uop cache, covering a few dozen most recently executed instructions. This loop cache generally does not have the 16-byte alignment restrictions of the uop cache. Now loop alignment can still be beneficial if: - a loop is cache-hot and its surroundings are not. - if the loop is so cache hot that the instruction flow becomes x86 decoder bandwidth limited But loop alignment is harmful if: - a loop is cache-cold - a loop's surroundings are cache-hot as well - two cache-hot loops are close to each other - if the loop fits into the loop cache - if the code flow is not decoder bandwidth limited and I'd argue that the latter five scenarios are much more common in the kernel, as our hottest loops are typically: - pointer chasing: this should fit into the loop cache in most cases and is typically data cache and address generation limited - generic memory ops (memset, memcpy, etc.): these generally fit into the loop cache as well, and are likewise data cache limited. So this patch packs loop addresses tightly as well. Acked-by:
Denys Vlasenko <dvlasenk@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jason Low <jason.low2@hp.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Link: http://lkml.kernel.org/r/20150410123017.GB19918@gmail.com Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usbLinus Torvalds authored
Pull USB fixes from Greg KH: "Here are some USB fixes and new device ids for 4.1-rc4. All are pretty minor, and have been in linux-next successfully" * tag 'usb-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: usb-storage: Add NO_WP_DETECT quirk for Lacie 059f:0651 devices Added another USB product ID for ELAN touchscreen quirks. xhci: gracefully handle xhci_irq dead device xhci: Solve full event ring by increasing TRBS_PER_SEGMENT to 256 xhci: fix isoc endpoint dequeue from advancing too far on transaction error usb: chipidea: debug: avoid out of bound read USB: visor: Match I330 phone more precisely USB: pl2303: Remove support for Samsung I330 USB: cp210x: add ID for KCF Technologies PRN device usb: gadget: remove incorrect __init/__exit annotations usb: phy: isp1301: work around tps65010 dependency usb: gadget: serial: fix re-ordering of tx data usb: gadget: hid: Fix static variable usage usb: gadget: configfs: Fix interfaces array NULL-termination usb: gadget: xilinx: fix devm_ioremap_resource() check usb: dwc3: dwc3-omap: correct the register macros
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/ttyLinus Torvalds authored
Pull tty/serial fixes from Greg KH: "Here's some TTY and serial driver fixes for reported issues. All of these have been in linux-next successfully" * tag 'tty-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: pty: Fix input race when closing tty/n_gsm.c: fix a memory leak when gsmtty is removed Revert "serial/amba-pl011: Leave the TX IRQ alone when the UART is not open" serial: omap: Fix error handling in probe earlycon: Revert log warnings
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/stagingLinus Torvalds authored
Pull staging / IIO driver fixes from Greg KH: "Here's some staging and iio driver fixes to resolve a number of reported issues. All of these have been in linux-next for a while" * tag 'staging-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (31 commits) iio: light: hid-sensor-prox: Fix memory leak in probe() iio: adc: cc10001: Add delay before setting START bit iio: adc: cc10001: Fix regulator_get_voltage() return value check iio: adc: cc10001: Fix incorrect use of power-up/power-down register staging: gdm724x: Correction of variable usage after applying ALIGN() iio: adc: cc10001: Fix the channel number mapping staging: vt6655: lock MACvWriteBSSIDAddress. staging: vt6655: CARDbUpdateTSF bss timestamp correct tsf counter value. staging: vt6655: vnt_tx_packet Correct TX order of OWNED_BY_NIC staging: vt6655: Fix 80211 control and management status reporting. staging: vt6655: implement IEEE80211_TX_STAT_NOACK_TRANSMITTED staging: vt6655: device_free_tx_buf use only ieee80211_tx_status_irqsafe staging: vt6656: use ieee80211_tx_info to select packet type. staging: rtl8712: freeing an ERR_PTR staging: sm750: remove incorrect __exit annotation iio: kfifo: Set update_needed to false only if a buffer was allocated iio: mcp320x: Fix occasional incorrect readings iio: accel: mma9553: check input value for activity period iio: accel: mma9553: add enable channel for activity iio: accel: mma9551_core: prevent buffer overrun ...
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-miscLinus Torvalds authored
Pull char/misc fix from Greg KH: "Here is one fix, in the extcon subsystem, that resolves a reported issue. It's been in linux-next for a number of weeks now, sorry for not getting it to you sooner" * tag 'char-misc-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: extcon: usb-gpio: register extcon device before IRQ registration
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git://git.kernel.org/pub/scm/linux/kernel/git/rw/umlLinus Torvalds authored
Pull UML hostfs fix from Richard Weinberger: "This contains a single fix for a regression introduced in 4.1-rc1" * 'for-linus-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: hostfs: Use correct mask for file mode
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git://git.infradead.org/linux-ubifsLinus Torvalds authored
Pull UBI bufix from Richard Weinberger: "This contains a single bug fix for the UBI block driver" * tag 'upstream-4.1-rc4' of git://git.infradead.org/linux-ubifs: UBI: block: Add missing cache flushes
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4Linus Torvalds authored
Pull ext4 fixes from Ted Ts'o: "Fix a number of ext4 bugs; the most serious of which is a bug in the lazytime mount optimization code where we could end up updating the timestamps to the wrong inode" * tag 'for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4: fix an ext3 collapse range regression in xfstests jbd2: fix r_count overflows leading to buffer overflow in journal recovery ext4: check for zero length extent explicitly ext4: fix NULL pointer dereference when journal restart fails ext4: remove unused function prototype from ext4.h ext4: don't save the error information if the block device is read-only ext4: fix lazytime optimization
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git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfsLinus Torvalds authored
Pull btrfs fixes from Chris Mason: "The first commit is a fix from Filipe for a very old extent buffer reuse race that triggered a BUG_ON. It hasn't come up often, I looked through old logs at FB and we hit it a handful of times over the last year. The rest are other corners he hit during testing" * 'for-linus-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: Btrfs: fix race when reusing stale extent buffers that leads to BUG_ON Btrfs: fix race between block group creation and their cache writeout Btrfs: fix panic when starting bg cache writeout after IO error Btrfs: fix crash after inode cache writeback failure
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git://git.linux-mips.org/pub/scm/ralf/upstream-linusLinus Torvalds authored
Pull MIPS fixes from Ralf Baechle: "Seven small fixes. The shortlog below is a good description so no need to elaborate. It has sat in linux-next and survived the usual automated testing by Imagination's test farm" * 'master' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: MIPS: tlb-r4k: Fix PG_ELPA comment MIPS: Fix up obsolete cpu_set usage MIPS: IP32: Fix build errors in reset code in DS1685 platform hook. MIPS: KVM: Fix unused variable build warning MIPS: traps: remove extra Tainted: line from __show_regs() output MIPS: Fix wrong CHECKFLAGS (sparse builds) with GCC 5.1 MIPS: Fix a preemption issue with thread's FPU defaults
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git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arcLinus Torvalds authored
Pull ARC fixes from Vineet Gupta. * tag 'arc-4.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: ARC: inline cache flush toggle helpers ARC: With earlycon in use, retire EARLY_PRINTK ARC: unbork !LLSC build
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git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-socLinus Torvalds authored
Pull ARM SoC fixes from Arnd Bergmann: "Nothing frightening this time, just smaller fixes in a number of places. The other changes contained here are: MAINTAINERS file updates: - The mach-gemini maintainer is back in action and has a new git tree - Krzysztof Kozlowski has volunteered to be a new co-maintainer for the samsung platforms - updates to the files that belong to Marvell mvebu Bug fixes: - The largest changes are on omap2, but are only to avoid some harmless warnings and to fix reset on omap4 - a small regression fix on tegra - multiple fixes for incorrect IRQ affinity on vexpress - the missing system controller on arm64 juno is added - one revert of a patch that was accidentally applied twice for mach-rockchip - two clock related DT fixes for mvebu - a workaround for suspend with old DT binaries on new exynos kernels - Another fix for suspend on exynos, needs to be backported" * tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (21 commits) MAINTAINERS: Add dts entries for some of the Marvell SoCs MAINTAINERS: ARM: EXYNOS: Add Krzysztof Kozlowski as co-maintainer ARM: EXYNOS: Use of_machine_is_compatible instead of soc_is_exynos4 ARM: EXYNOS: Fix failed second suspend on Exynos4 Revert "ARM: rockchip: fix undefined instruction of reset_ctrl_regs" ARM: EXYNOS: Fix dereference of ERR_PTR returned by of_genpd_get_from_provider ARM: EXYNOS: Don't try to initialize suspend on old DT ARM: dts: Add keep-power-in-suspend to WiFi SDIO node for Peach Boards ARM: gemini: fix compiler warning due wrong data type ARM: vexpress/tc2: Add interrupt-affinity to the PMU node ARM: vexpress/ca9: Add interrupt-affinity to the PMU node ARM: vexpress/ca9: Add unified-cache property to l2 cache node ARM64: juno: add sp810 support and fix sp804 clock frequency ARM: Gemini: Maintainers update ARM: OMAP2+: Remove bogus struct clk comparison for timer clock ARM: dove: Add clock-names to CuBox Si5351 clk generator ARM: AM33xx+: hwmod: re-use omap4 implementations for reset functionality ARM: OMAP4+: PRM: add support for passing status register/bit info to reset ARM: AM43xx: hwmod: add VPFE hwmod entries ARM: mvebu: Fix the main PLL frequency on Armada 375, 38x and 39x SoCs ...
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