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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: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210518191303.4135296-7-hpa@zytor.com
This commit is contained in:
H. Peter Anvin (Intel) 2021-05-18 12:13:03 -07:00 committed by Thomas Gleixner
parent b337b4965e
commit 2978996f62
2 changed files with 60 additions and 29 deletions
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87
arch/x86/entry/common.c
View File

@ -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);

2
arch/x86/include/asm/syscall.h
View File

@ -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);