diff options
| author | Andy Lutomirski <luto@kernel.org> | 2020-06-26 19:21:12 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-07-01 10:00:25 +0200 |
| commit | d1721250f3ffed9afba3e1fb729947cec64c5a8a (patch) | |
| tree | 44a4bb9b6a00cbdda62e36ec124c89fa093a9253 /arch/x86/entry/common.c | |
| parent | x86/entry: Assert that syscalls are on the right stack (diff) | |
| download | linux-d1721250f3ffed9afba3e1fb729947cec64c5a8a.tar.xz linux-d1721250f3ffed9afba3e1fb729947cec64c5a8a.zip | |
x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C
The SYSENTER asm (32-bit and compat) contains fixups for regs->sp and
regs->flags. Move the fixups into C and fix some comments while at it.
This is a valid cleanup all by itself, and it also simplifies the
subsequent patch that will fix Xen PV SYSENTER.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/fe62bef67eda7fac75b8f3dbafccf571dc4ece6b.1593191971.git.luto@kernel.org
Diffstat (limited to 'arch/x86/entry/common.c')
| -rw-r--r-- | arch/x86/entry/common.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index ed8ccc820995..f392a8bcd1c3 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -522,6 +522,18 @@ __visible noinstr long do_fast_syscall_32(struct pt_regs *regs) (regs->flags & (X86_EFLAGS_RF | X86_EFLAGS_TF | X86_EFLAGS_VM)) == 0; #endif } + +/* Returns 0 to return using IRET or 1 to return using SYSEXIT/SYSRETL. */ +__visible noinstr long do_SYSENTER_32(struct pt_regs *regs) +{ + /* SYSENTER loses RSP, but the vDSO saved it in RBP. */ + regs->sp = regs->bp; + + /* SYSENTER clobbers EFLAGS.IF. Assume it was set in usermode. */ + regs->flags |= X86_EFLAGS_IF; + + return do_fast_syscall_32(regs); +} #endif SYSCALL_DEFINE0(ni_syscall) |