The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 93efbde2c331004d8053f04b4bf0ca3e630b474a
Gitweb: https://git.kernel.org/tip/93efbde2c331004d8053f04b4bf0ca3e630b474a
Author: Andy Lutomirski <luto@xxxxxxxxxx>
AuthorDate: Wed, 20 Nov 2019 22:12:38 -08:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 26 Nov 2019 21:53:34 +01:00
x86/traps: Disentangle the 32-bit and 64-bit doublefault code
The 64-bit doublefault handler is much nicer than the 32-bit one.
As a first step toward unifying them, make the 64-bit handler
self-contained. This should have no effect no functional effect
except in the odd case of x86_64 with CONFIG_DOUBLEFAULT=n in which
case it will change the logging a bit.
This also gets rid of CONFIG_DOUBLEFAULT configurability on 64-bit
kernels. It didn't do anything useful -- CONFIG_DOUBLEFAULT=n
didn't actually disable doublefault handling on x86_64.
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/Kconfig.debug | 2 +-
arch/x86/include/asm/processor.h | 1 -
arch/x86/kernel/doublefault.c | 11 -----------
arch/x86/kernel/traps.c | 12 +++---------
4 files changed, 4 insertions(+), 22 deletions(-)
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 409c00f..c4eab8e 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -117,7 +117,7 @@ config DEBUG_WX
config DOUBLEFAULT
default y
- bool "Enable doublefault exception handler" if EXPERT
+ bool "Enable doublefault exception handler" if EXPERT && X86_32
---help---
This option allows trapping of rare doublefault exceptions that
would otherwise cause a system to silently reboot. Disabling this
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index e51afbb..f6c6300 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -997,7 +997,6 @@ bool xen_set_default_idle(void);
#endif
void stop_this_cpu(void *dummy);
-void df_debug(struct pt_regs *regs, long error_code);
void microcode_check(void);
enum l1tf_mitigations {
diff --git a/arch/x86/kernel/doublefault.c b/arch/x86/kernel/doublefault.c
index 0d6c657..0b3c616 100644
--- a/arch/x86/kernel/doublefault.c
+++ b/arch/x86/kernel/doublefault.c
@@ -72,15 +72,4 @@ struct x86_hw_tss doublefault_tss __cacheline_aligned = {
.__cr3 = __pa_nodebug(swapper_pg_dir),
};
-/* dummy for do_double_fault() call */
-void df_debug(struct pt_regs *regs, long error_code) {}
-
-#else /* !CONFIG_X86_32 */
-
-void df_debug(struct pt_regs *regs, long error_code)
-{
- pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
- show_regs(regs);
- panic("Machine halted.");
-}
#endif
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index c903121..76381b0 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -411,15 +411,9 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsign
handle_stack_overflow("kernel stack overflow (double-fault)", regs, cr2);
#endif
-#ifdef CONFIG_DOUBLEFAULT
- df_debug(regs, error_code);
-#endif
- /*
- * This is always a kernel trap and never fixable (and thus must
- * never return).
- */
- for (;;)
- die(str, regs, error_code);
+ pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code);
+ show_regs(regs);
+ panic("Machine halted.");
}
#endif
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