Commit 28ceac69 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'powerpc-5.13-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux 

Pull powerpc fixes from Michael Ellerman:

 - Fix breakage of strace (and other ptracers etc.) when using the new
   scv ABI (Power9 or later with glibc >= 2.33).

 - Fix early_ioremap() on 64-bit, which broke booting on some machines.

Thanks to Dmitry V. Levin, Nicholas Piggin, Alexey Kardashevskiy, and
Christophe Leroy.

* tag 'powerpc-5.13-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s/syscall: Fix ptrace syscall info with scv syscalls
  powerpc/64s/syscall: Use pt_regs.trap to distinguish syscall ABI difference between sc and scv syscalls
  powerpc: Fix early setup to make early_ioremap() work
parents 4d762034 d72500f9

Documentation/powerpc/syscall64-abi.rst

+10 −0
Original line number Diff line number Diff line
@@ -109,6 +109,16 @@ auxiliary vector. 


scv 0 syscalls will always behave as PPC_FEATURE2_HTM_NOSC.



ptrace

------

When ptracing system calls (PTRACE_SYSCALL), the pt_regs.trap value contains

the system call type that can be used to distinguish between sc and scv 0

system calls, and the different register conventions can be accounted for.



If the value of (pt_regs.trap & 0xfff0) is 0xc00 then the system call was

performed with the sc instruction, if it is 0x3000 then the system call was

performed with the scv 0 instruction.



vsyscall

========

arch/powerpc/include/asm/ptrace.h

+26 −19
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#ifndef _ASM_POWERPC_PTRACE_H

#define _ASM_POWERPC_PTRACE_H



#include <linux/err.h>

#include <uapi/asm/ptrace.h>

#include <asm/asm-const.h>
@@ -152,25 +153,6 @@ extern unsigned long profile_pc(struct pt_regs *regs); 
long do_syscall_trace_enter(struct pt_regs *regs);

void do_syscall_trace_leave(struct pt_regs *regs);



#define kernel_stack_pointer(regs) ((regs)->gpr[1])

static inline int is_syscall_success(struct pt_regs *regs)

{

	return !(regs->ccr & 0x10000000);

}



static inline long regs_return_value(struct pt_regs *regs)

{

	if (is_syscall_success(regs))

		return regs->gpr[3];

	else

		return -regs->gpr[3];

}



static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)

{

	regs->gpr[3] = rc;

}



#ifdef __powerpc64__

#define user_mode(regs) ((((regs)->msr) >> MSR_PR_LG) & 0x1)

#else
@@ -235,6 +217,31 @@ static __always_inline void set_trap_norestart(struct pt_regs *regs) 
	regs->trap |= 0x1;

}



#define kernel_stack_pointer(regs) ((regs)->gpr[1])

static inline int is_syscall_success(struct pt_regs *regs)

{

	if (trap_is_scv(regs))

		return !IS_ERR_VALUE((unsigned long)regs->gpr[3]);

	else

		return !(regs->ccr & 0x10000000);

}



static inline long regs_return_value(struct pt_regs *regs)

{

	if (trap_is_scv(regs))

		return regs->gpr[3];



	if (is_syscall_success(regs))

		return regs->gpr[3];

	else

		return -regs->gpr[3];

}



static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)

{

	regs->gpr[3] = rc;

}



#define arch_has_single_step()	(1)

#define arch_has_block_step()	(true)

#define ARCH_HAS_USER_SINGLE_STEP_REPORT

arch/powerpc/include/asm/syscall.h

+26 −16
Original line number Diff line number Diff line
@@ -41,12 +41,18 @@ static inline void syscall_rollback(struct task_struct *task, 
static inline long syscall_get_error(struct task_struct *task,

				     struct pt_regs *regs)

{

	if (trap_is_scv(regs)) {

		unsigned long error = regs->gpr[3];



		return IS_ERR_VALUE(error) ? error : 0;

	} else {

		/*

		 * If the system call failed,

		 * regs->gpr[3] contains a positive ERRORCODE.

		 */

		return (regs->ccr & 0x10000000UL) ? -regs->gpr[3] : 0;

	}

}



static inline long syscall_get_return_value(struct task_struct *task,

					    struct pt_regs *regs)
@@ -58,11 +64,14 @@ static inline void syscall_set_return_value(struct task_struct *task, 
					    struct pt_regs *regs,

					    int error, long val)

{

	if (trap_is_scv(regs)) {

		regs->gpr[3] = (long) error ?: val;

	} else {

		/*

	 * In the general case it's not obvious that we must deal with CCR

	 * here, as the syscall exit path will also do that for us. However

	 * there are some places, eg. the signal code, which check ccr to

	 * decide if the value in r3 is actually an error.

		 * In the general case it's not obvious that we must deal with

		 * CCR here, as the syscall exit path will also do that for us.

		 * However there are some places, eg. the signal code, which

		 * check ccr to decide if the value in r3 is actually an error.

		 */

		if (error) {

			regs->ccr |= 0x10000000L;
@@ -72,6 +81,7 @@ static inline void syscall_set_return_value(struct task_struct *task, 
			regs->gpr[3] = val;

		}

	}

}



static inline void syscall_get_arguments(struct task_struct *task,

					 struct pt_regs *regs,

arch/powerpc/kernel/setup_64.c

+2 −2
Original line number Diff line number Diff line
@@ -369,11 +369,11 @@ void __init early_setup(unsigned long dt_ptr) 
	apply_feature_fixups();

	setup_feature_keys();



	early_ioremap_setup();



	/* Initialize the hash table or TLB handling */

	early_init_mmu();



	early_ioremap_setup();



	/*

	 * After firmware and early platform setup code has set things up,

	 * we note the SPR values for configurable control/performance

tools/testing/selftests/seccomp/seccomp_bpf.c

+18 −9
Original line number Diff line number Diff line
@@ -1753,9 +1753,17 @@ TEST_F(TRACE_poke, getpid_runs_normally) 
# define SYSCALL_RET_SET(_regs, _val)				\

	do {							\

		typeof(_val) _result = (_val);			\

		if ((_regs.trap & 0xfff0) == 0x3000) {		\

			/*					\

		 * A syscall error is signaled by CR0 SO bit	\

		 * and the code is stored as a positive value.	\

			 * scv 0 system call uses -ve result	\

			 * for error, so no need to adjust.	\

			 */					\

			SYSCALL_RET(_regs) = _result;		\

		} else {					\

			/*					\

			 * A syscall error is signaled by the	\

			 * CR0 SO bit and the code is stored as	\

			 * a positive value.			\

			 */					\

			if (_result < 0) {			\

				SYSCALL_RET(_regs) = -_result;	\
@@ -1764,6 +1772,7 @@ TEST_F(TRACE_poke, getpid_runs_normally) 
				SYSCALL_RET(_regs) = _result;	\

				(_regs).ccr &= ~0x10000000;	\

			}					\

		}						\

	} while (0)

# define SYSCALL_RET_SET_ON_PTRACE_EXIT

#elif defined(__s390__)