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| author | Brian Gerst <brgerst@gmail.com> | 2019-12-19 06:58:12 -0500 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-01-08 19:40:51 +0100 |
| commit | 2b10906f2d25515bba58070b8183babc89063597 (patch) | |
| tree | 9b6a4c28c47d3bbd438f0264a2ccb693471ee652 /arch/x86/kernel | |
| parent | f444a5ff95dce07cf4353cbb85fc3e785019d430 (diff) | |
| download | linux-stable-2b10906f2d25515bba58070b8183babc89063597.tar.gz linux-stable-2b10906f2d25515bba58070b8183babc89063597.tar.bz2 linux-stable-2b10906f2d25515bba58070b8183babc89063597.zip | |
x86: Remove force_iret()
force_iret() was originally intended to prevent the return to user mode with
the SYSRET or SYSEXIT instructions, in cases where the register state could
have been changed to be incompatible with those instructions. The entry code
has been significantly reworked since then, and register state is validated
before SYSRET or SYSEXIT are used. force_iret() no longer serves its original
purpose and can be eliminated.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20191219115812.102620-1-brgerst@gmail.com
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/process_32.c | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/process_64.c | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/signal.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/vm86_32.c | 1 |
4 files changed, 0 insertions, 5 deletions
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 323499f48858..5052ced43373 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -124,7 +124,6 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) regs->ip = new_ip; regs->sp = new_sp; regs->flags = X86_EFLAGS_IF; - force_iret(); } EXPORT_SYMBOL_GPL(start_thread); diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 506d66830d4d..ffd497804dbc 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -394,7 +394,6 @@ start_thread_common(struct pt_regs *regs, unsigned long new_ip, regs->cs = _cs; regs->ss = _ss; regs->flags = X86_EFLAGS_IF; - force_iret(); } void diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 8eb7193e158d..8a29573851a3 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -151,8 +151,6 @@ static int restore_sigcontext(struct pt_regs *regs, err |= fpu__restore_sig(buf, IS_ENABLED(CONFIG_X86_32)); - force_iret(); - return err; } diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c index a76c12b38e92..91d55454e702 100644 --- a/arch/x86/kernel/vm86_32.c +++ b/arch/x86/kernel/vm86_32.c @@ -381,7 +381,6 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus) mark_screen_rdonly(tsk->mm); memcpy((struct kernel_vm86_regs *)regs, &vm86regs, sizeof(vm86regs)); - force_iret(); return regs->ax; } |