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Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/entry/common.c29
1 files changed, 20 insertions, 9 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 48512c7944e7..2f84c7ca74ea 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -60,16 +60,10 @@ __visible noinstr void do_syscall_64(unsigned long nr, struct pt_regs *regs)
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
static __always_inline unsigned int syscall_32_enter(struct pt_regs *regs)
{
- unsigned int nr = (unsigned int)regs->orig_ax;
-
if (IS_ENABLED(CONFIG_IA32_EMULATION))
current_thread_info()->status |= TS_COMPAT;
- /*
- * 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.
- */
- return (unsigned int)syscall_enter_from_user_mode(regs, nr);
+
+ return (unsigned int)regs->orig_ax;
}
/*
@@ -91,15 +85,29 @@ __visible noinstr void do_int80_syscall_32(struct pt_regs *regs)
{
unsigned int nr = syscall_32_enter(regs);
+ /*
+ * 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.
+ */
+ nr = (unsigned int)syscall_enter_from_user_mode(regs, nr);
+
do_syscall_32_irqs_on(regs, nr);
syscall_exit_to_user_mode(regs);
}
static noinstr bool __do_fast_syscall_32(struct pt_regs *regs)
{
- unsigned int nr = syscall_32_enter(regs);
+ unsigned int nr = syscall_32_enter(regs);
int res;
+ /*
+ * This cannot use syscall_enter_from_user_mode() as it has to
+ * fetch EBP before invoking any of the syscall entry work
+ * functions.
+ */
+ syscall_enter_from_user_mode_prepare(regs);
+
instrumentation_begin();
/* Fetch EBP from where the vDSO stashed it. */
if (IS_ENABLED(CONFIG_X86_64)) {
@@ -122,6 +130,9 @@ 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);
+
/* Now this is just like a normal syscall. */
do_syscall_32_irqs_on(regs, nr);
syscall_exit_to_user_mode(regs);