From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [RFC PATCH 3/8] powerpc/irq: don't use current_stack_pointer() in do_IRQ()
Date: Mon, 23 Dec 2019 15:26:13 +0000 (UTC) [thread overview]
Message-ID: <9bd99cf0e97fd62e63c4a14247dee060c8f743e1.1577114567.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1577114567.git.christophe.leroy@c-s.fr>
Before commit 7306e83ccf5c ("powerpc: Don't use CURRENT_THREAD_INFO to
find the stack"), the current stack base address was obtained by
calling current_thread_info(). That inline function was simply masking
out the value of r1.
In that commit, it was changed to using current_stack_pointer(), which
is an heavier function as it is an outline assembly function which
cannot be inlined and which reads the content of the stack at 0(r1)
Create stack_pointer() function which returns the value of r1 and use
it instead.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Fixes: 7306e83ccf5c ("powerpc: Don't use CURRENT_THREAD_INFO to find the stack")
---
arch/powerpc/include/asm/reg.h | 8 ++++++++
arch/powerpc/kernel/irq.c | 2 +-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 1aa46dff0957..bc14fca9b13b 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1466,6 +1466,14 @@ static inline void update_power8_hid0(unsigned long hid0)
*/
asm volatile("sync; mtspr %0,%1; isync":: "i"(SPRN_HID0), "r"(hid0));
}
+
+static __always_inline unsigned long stack_pointer(void)
+{
+ register unsigned long r1 asm("r1");
+
+ return r1;
+}
+
#endif /* __ASSEMBLY__ */
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_REG_H */
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 4690e5270806..410accba865d 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -680,7 +680,7 @@ void do_IRQ(struct pt_regs *regs)
void *cursp, *irqsp, *sirqsp;
/* Switch to the irq stack to handle this */
- cursp = (void *)(current_stack_pointer() & ~(THREAD_SIZE - 1));
+ cursp = (void *)(stack_pointer() & ~(THREAD_SIZE - 1));
irqsp = hardirq_ctx[raw_smp_processor_id()];
sirqsp = softirq_ctx[raw_smp_processor_id()];
--
2.13.3
next prev parent reply other threads:[~2019-12-23 15:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-23 15:26 [RFC PATCH 0/8] Accelarate IRQ entry Christophe Leroy
2019-12-23 15:26 ` [RFC PATCH 1/8] powerpc/32: drop ksp_limit based stack overflow detection Christophe Leroy
2019-12-23 15:26 ` [RFC PATCH 2/8] powerpc/irq: inline call_do_irq() and call_do_softirq() on PPC32 Christophe Leroy
2019-12-23 15:26 ` Christophe Leroy [this message]
2019-12-23 15:26 ` [RFC PATCH 4/8] powerpc/irq: move set_irq_regs() closer to irq_enter/exit() Christophe Leroy
2019-12-23 15:26 ` [RFC PATCH 5/8] powerpc/irq: move stack overflow verification Christophe Leroy
2019-12-23 15:26 ` [RFC PATCH 6/8] powerpc/irq: cleanup check_stack_overflow() a bit Christophe Leroy
2019-12-23 15:26 ` [RFC PATCH 7/8] powerpc/32: use IRQ stack immediately on IRQ exception Christophe Leroy
2019-12-23 15:26 ` [RFC PATCH 8/8] powerpc/irq: drop softirq stack Christophe Leroy
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