diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2020-06-10 08:37:01 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-06-11 15:15:29 +0200 |
| commit | f0178fc01fe46bab6a95415f5647d1a74efcad1b (patch) | |
| tree | bf263d8cacf2ada33dea4cbc16ee5fd46b0109d4 /arch/x86/entry | |
| parent | 2823e83a3dc0f54d23db67ca07d74b9c8bb1fdda (diff) | |
x86/entry: Unbreak __irqentry_text_start/end magic
The entry rework moved interrupt entry code from the irqentry to the
noinstr section which made the irqentry section empty.
This breaks boundary checks which rely on the __irqentry_text_start/end
markers to find out whether a function in a stack trace is
interrupt/exception entry code. This affects the function graph tracer and
filter_irq_stacks().
As the IDT entry points are all sequentialy emitted this is rather simple
to unbreak by injecting __irqentry_text_start/end as global labels.
To make this work correctly:
- Remove the IRQENTRY_TEXT section from the x86 linker script
- Define __irqentry so it breaks the build if it's used
- Adjust the entry mirroring in PTI
- Remove the redundant kprobes and unwinder bound checks
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/entry')
| -rw-r--r-- | arch/x86/entry/entry_32.S | 11 | ||||
| -rw-r--r-- | arch/x86/entry/entry_64.S | 11 |
2 files changed, 20 insertions, 2 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 2d29f77a3601..024d7d276cd4 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -743,10 +743,19 @@ SYM_CODE_END(asm_\cfunc) /* * Include the defines which emit the idt entries which are shared - * shared between 32 and 64 bit. + * shared between 32 and 64 bit and emit the __irqentry_text_* markers + * so the stacktrace boundary checks work. */ + .align 16 + .globl __irqentry_text_start +__irqentry_text_start: + #include <asm/idtentry.h> + .align 16 + .globl __irqentry_text_end +__irqentry_text_end: + /* * %eax: prev task * %edx: next task diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 8ecaeee53653..d2a00c97e53f 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -478,10 +478,19 @@ SYM_CODE_END(\asmsym) /* * Include the defines which emit the idt entries which are shared - * shared between 32 and 64 bit. + * shared between 32 and 64 bit and emit the __irqentry_text_* markers + * so the stacktrace boundary checks work. */ + .align 16 + .globl __irqentry_text_start +__irqentry_text_start: + #include <asm/idtentry.h> + .align 16 + .globl __irqentry_text_end +__irqentry_text_end: + SYM_CODE_START_LOCAL(common_interrupt_return) SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL) #ifdef CONFIG_DEBUG_ENTRY |