Commit 2978996f authored by H. Peter Anvin (Intel)'s avatar H. Peter Anvin (Intel) Committed by Thomas Gleixner
Browse files

x86/entry: Use int everywhere for system call numbers 



System call numbers are defined as int, so use int everywhere for system
call numbers. This is strictly a cleanup; it should not change anything
user visible; all ABI changes have been done in the preceeding patches.

[ tglx: Replaced the unsigned long cast ]

Signed-off-by: default avatarH. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210518191303.4135296-7-hpa@zytor.com
parent b337b496

arch/x86/entry/common.c

+59 −28
Original line number Diff line number Diff line
@@ -36,49 +36,81 @@ 
#include <asm/irq_stack.h>



#ifdef CONFIG_X86_64

__visible noinstr void do_syscall_64(struct pt_regs *regs, unsigned long nr)



static __always_inline bool do_syscall_x64(struct pt_regs *regs, int nr)

{

	/*

	 * Convert negative numbers to very high and thus out of range

	 * numbers for comparisons.

	 */

	unsigned int unr = nr;



	if (likely(unr < NR_syscalls)) {

		unr = array_index_nospec(unr, NR_syscalls);

		regs->ax = sys_call_table[unr](regs);

		return true;

	}

	return false;

}



static __always_inline bool do_syscall_x32(struct pt_regs *regs, int nr)

{

	/*

	 * Adjust the starting offset of the table, and convert numbers

	 * < __X32_SYSCALL_BIT to very high and thus out of range

	 * numbers for comparisons.

	 */

	unsigned int xnr = nr - __X32_SYSCALL_BIT;



	if (IS_ENABLED(CONFIG_X86_X32_ABI) && likely(xnr < X32_NR_syscalls)) {

		xnr = array_index_nospec(xnr, X32_NR_syscalls);

		regs->ax = x32_sys_call_table[xnr](regs);

		return true;

	}

	return false;

}



__visible noinstr void do_syscall_64(struct pt_regs *regs, int nr)

{

	add_random_kstack_offset();

	nr = syscall_enter_from_user_mode(regs, nr);



	instrumentation_begin();

	if (likely(nr < NR_syscalls)) {

		nr = array_index_nospec(nr, NR_syscalls);

		regs->ax = sys_call_table[nr](regs);

#ifdef CONFIG_X86_X32_ABI

	} else if (likely((nr & __X32_SYSCALL_BIT) &&

			  (nr & ~__X32_SYSCALL_BIT) < X32_NR_syscalls)) {

		nr = array_index_nospec(nr & ~__X32_SYSCALL_BIT,

					X32_NR_syscalls);

		regs->ax = x32_sys_call_table[nr](regs);

#endif

	} else if (unlikely((int)nr != -1)) {



	if (!do_syscall_x64(regs, nr) && !do_syscall_x32(regs, nr) && nr != -1) {

		/* Invalid system call, but still a system call. */

		regs->ax = __x64_sys_ni_syscall(regs);

	}



	instrumentation_end();

	syscall_exit_to_user_mode(regs);

}

#endif



#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)

static __always_inline unsigned int syscall_32_enter(struct pt_regs *regs)

static __always_inline int syscall_32_enter(struct pt_regs *regs)

{

	if (IS_ENABLED(CONFIG_IA32_EMULATION))

		current_thread_info()->status |= TS_COMPAT;



	return (unsigned int)regs->orig_ax;

	return (int)regs->orig_ax;

}



/*

 * Invoke a 32-bit syscall.  Called with IRQs on in CONTEXT_KERNEL.

 */

static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs,

						  unsigned int nr)

static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs, int nr)

{

	if (likely(nr < IA32_NR_syscalls)) {

		nr = array_index_nospec(nr, IA32_NR_syscalls);

		regs->ax = ia32_sys_call_table[nr](regs);

	} else if (unlikely((int)nr != -1)) {

	/*

	 * Convert negative numbers to very high and thus out of range

	 * numbers for comparisons.

	 */

	unsigned int unr = nr;



	if (likely(unr < IA32_NR_syscalls)) {

		unr = array_index_nospec(unr, IA32_NR_syscalls);

		regs->ax = ia32_sys_call_table[unr](regs);

	} else if (nr != -1) {

		regs->ax = __ia32_sys_ni_syscall(regs);

	}

}
@@ -86,15 +118,15 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs, 
/* Handles int $0x80 */

__visible noinstr void do_int80_syscall_32(struct pt_regs *regs)

{

	unsigned int nr = syscall_32_enter(regs);

	int nr = syscall_32_enter(regs);



	add_random_kstack_offset();

	/*

	 * Subtlety here: if ptrace pokes something larger than 2^32-1 into

	 * orig_ax, the unsigned int return value truncates it.  This may

	 * or may not be necessary, but it matches the old asm behavior.

	 * Subtlety here: if ptrace pokes something larger than 2^31-1 into

	 * orig_ax, the int return value truncates it. This matches

	 * the semantics of syscall_get_nr().

	 */

	nr = (unsigned int)syscall_enter_from_user_mode(regs, nr);

	nr = syscall_enter_from_user_mode(regs, nr);

	instrumentation_begin();



	do_syscall_32_irqs_on(regs, nr);
@@ -105,7 +137,7 @@ __visible noinstr void do_int80_syscall_32(struct pt_regs *regs) 


static noinstr bool __do_fast_syscall_32(struct pt_regs *regs)

{

	unsigned int nr = syscall_32_enter(regs);

	int nr = syscall_32_enter(regs);

	int res;



	add_random_kstack_offset();
@@ -140,8 +172,7 @@ static noinstr bool __do_fast_syscall_32(struct pt_regs *regs) 
		return false;

	}



	/* The case truncates any ptrace induced syscall nr > 2^32 -1 */

	nr = (unsigned int)syscall_enter_from_user_mode_work(regs, nr);

	nr = syscall_enter_from_user_mode_work(regs, nr);



	/* Now this is just like a normal syscall. */

	do_syscall_32_irqs_on(regs, nr);

arch/x86/include/asm/syscall.h

+1 −1
Original line number Diff line number Diff line
@@ -159,7 +159,7 @@ static inline int syscall_get_arch(struct task_struct *task) 
		? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;

}



void do_syscall_64(struct pt_regs *regs, unsigned long nr);

void do_syscall_64(struct pt_regs *regs, int nr);

void do_int80_syscall_32(struct pt_regs *regs);

long do_fast_syscall_32(struct pt_regs *regs);