diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2020-05-21 22:05:34 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-06-11 15:15:11 +0200 |
| commit | 633260fa143bbed05e65dc557a492667dfdc45bb (patch) | |
| tree | 7a9dfe7624f2df0400408aa401bd80aca41c3f90 /arch/x86/entry/calling.h | |
| parent | 79b9c183021ef3f5ca2d5168cd3fd442580eca09 (diff) | |
x86/irq: Convey vector as argument and not in ptregs
Device interrupts which go through do_IRQ() or the spurious interrupt
handler have their separate entry code on 64 bit for no good reason.
Both 32 and 64 bit transport the vector number through ORIG_[RE]AX in
pt_regs. Further the vector number is forced to fit into an u8 and is
complemented and offset by 0x80 so it's in the signed character
range. Otherwise GAS would expand the pushq to a 5 byte instruction for any
vector > 0x7F.
Treat the vector number like an error code and hand it to the C function as
argument. This allows to get rid of the extra entry code in a later step.
Simplify the error code push magic by implementing the pushq imm8 via a
'.byte 0x6a, vector' sequence so GAS is not able to screw it up. As the
pushq imm8 is sign extending the resulting error code needs to be truncated
to 8 bits in C code.
Originally-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202118.796915981@linutronix.de
Diffstat (limited to 'arch/x86/entry/calling.h')
| -rw-r--r-- | arch/x86/entry/calling.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 1c7f13bb6728..98da0d3c0b1a 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -341,7 +341,10 @@ For 32-bit we have the following conventions - kernel is built with #endif .endm -#endif /* CONFIG_X86_64 */ +#else /* CONFIG_X86_64 */ +# undef UNWIND_HINT_IRET_REGS +# define UNWIND_HINT_IRET_REGS +#endif /* !CONFIG_X86_64 */ .macro STACKLEAK_ERASE #ifdef CONFIG_GCC_PLUGIN_STACKLEAK |