diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2020-05-21 23:05:34 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-06-11 16:15:11 +0300 |
| commit | 633260fa143bbed05e65dc557a492667dfdc45bb (patch) | |
| tree | 7a9dfe7624f2df0400408aa401bd80aca41c3f90 /arch/x86/kernel/irq.c | |
| parent | 79b9c183021ef3f5ca2d5168cd3fd442580eca09 (diff) | |
| download | linux-633260fa143bbed05e65dc557a492667dfdc45bb.tar.xz | |
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/kernel/irq.c')
| -rw-r--r-- | arch/x86/kernel/irq.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 252065d32ab5..c7669363251a 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -227,14 +227,18 @@ u64 arch_irq_stat(void) * SMP cross-CPU interrupts have their own specific * handlers). */ -__visible void __irq_entry do_IRQ(struct pt_regs *regs) +__visible void __irq_entry do_IRQ(struct pt_regs *regs, unsigned long vector) { struct pt_regs *old_regs = set_irq_regs(regs); - struct irq_desc * desc; - /* high bit used in ret_from_ code */ - unsigned vector = ~regs->orig_ax; + struct irq_desc *desc; entering_irq(); + /* + * The push in the entry ASM code which stores the vector number on + * the stack in the error code slot is sign expanding. Just use the + * lower 8 bits. + */ + vector &= 0xFF; /* entering_irq() tells RCU that we're not quiescent. Check it. */ RCU_LOCKDEP_WARN(!rcu_is_watching(), "IRQ failed to wake up RCU"); @@ -249,7 +253,7 @@ __visible void __irq_entry do_IRQ(struct pt_regs *regs) ack_APIC_irq(); if (desc == VECTOR_UNUSED) { - pr_emerg_ratelimited("%s: %d.%d No irq handler for vector\n", + pr_emerg_ratelimited("%s: %d.%lu No irq handler for vector\n", __func__, smp_processor_id(), vector); } else { |