[PATCH v2 3/9] powerpc/64e: remove implicit soft-masking and interrupt exit restart logic
Nicholas Piggin
npiggin at gmail.com
Wed Jun 30 08:19:51 AEST 2021
The implicit soft-masking to speed up interrupt return was going to be
used by 64e as well, but it was not ready in time. 64e always disables
MSR[EE] when exiting from interrupt and syscall.
Disable it for now.
Fixes: 9d1988ca87dd ("powerpc/64: treat low kernel text as irqs soft-masked")
Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
arch/powerpc/include/asm/interrupt.h | 33 ++++++++++++++++++++--------
arch/powerpc/kernel/exceptions-64e.S | 12 +---------
arch/powerpc/kernel/interrupt_64.S | 16 +++++++++++++-
3 files changed, 40 insertions(+), 21 deletions(-)
diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
index 8b4b1e84e110..f13c93b033c7 100644
--- a/arch/powerpc/include/asm/interrupt.h
+++ b/arch/powerpc/include/asm/interrupt.h
@@ -73,20 +73,34 @@
#include <asm/kprobes.h>
#include <asm/runlatch.h>
-#ifdef CONFIG_PPC64
+#ifdef CONFIG_PPC_BOOK3S_64
extern char __end_soft_masked[];
unsigned long search_kernel_restart_table(unsigned long addr);
-#endif
-#ifdef CONFIG_PPC_BOOK3S_64
DECLARE_STATIC_KEY_FALSE(interrupt_exit_not_reentrant);
+static inline bool is_implicit_soft_masked(struct pt_regs *regs)
+{
+ if (regs->msr & MSR_PR)
+ return false;
+
+ if (regs->nip >= (unsigned long)__end_soft_masked)
+ return false;
+
+ return true;
+}
+
static inline void srr_regs_clobbered(void)
{
local_paca->srr_valid = 0;
local_paca->hsrr_valid = 0;
}
#else
+static inline bool is_implicit_soft_masked(struct pt_regs *regs)
+{
+ return false;
+}
+
static inline void srr_regs_clobbered(void)
{
}
@@ -150,11 +164,13 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup
*/
if (TRAP(regs) != INTERRUPT_PROGRAM) {
CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
- BUG_ON(regs->nip < (unsigned long)__end_soft_masked);
+ BUG_ON(is_implicit_soft_masked(regs));
}
+#ifdef CONFIG_PPC_BOOK3S
/* Move this under a debugging check */
if (arch_irq_disabled_regs(regs))
BUG_ON(search_kernel_restart_table(regs->nip));
+#endif
}
#endif
@@ -244,10 +260,9 @@ static inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct inte
local_paca->irq_soft_mask = IRQS_ALL_DISABLED;
local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
- if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !(regs->msr & MSR_PR) &&
- regs->nip < (unsigned long)__end_soft_masked) {
- // Kernel code running below __end_soft_masked is
- // implicitly soft-masked.
+ if (is_implicit_soft_masked(regs)) {
+ // Adjust regs->softe soft implicit soft-mask, so
+ // arch_irq_disabled_regs(regs) behaves as expected.
regs->softe = IRQS_ALL_DISABLED;
}
@@ -282,6 +297,7 @@ static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct inter
*/
#ifdef CONFIG_PPC64
+#ifdef CONFIG_PPC_BOOK3S
if (arch_irq_disabled_regs(regs)) {
unsigned long rst = search_kernel_restart_table(regs->nip);
if (rst)
@@ -289,7 +305,6 @@ static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct inter
}
#endif
-#ifdef CONFIG_PPC64
if (nmi_disables_ftrace(regs))
this_cpu_set_ftrace_enabled(state->ftrace_enabled);
diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index d634bfceed2c..1401787b0b93 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -342,17 +342,7 @@ ret_from_mc_except:
#define PROLOG_ADDITION_MASKABLE_GEN(n) \
lbz r10,PACAIRQSOFTMASK(r13); /* are irqs soft-masked? */ \
andi. r10,r10,IRQS_DISABLED; /* yes -> go out of line */ \
- bne masked_interrupt_book3e_##n; \
- /* Kernel code below __end_soft_masked is implicitly masked */ \
- andi. r10,r11,MSR_PR; \
- bne 1f; /* user -> not masked */ \
- std r14,PACA_EXGEN+EX_R14(r13); \
- LOAD_REG_IMMEDIATE_SYM(r14, r10, __end_soft_masked); \
- mfspr r10,SPRN_SRR0; \
- cmpld r10,r14; \
- ld r14,PACA_EXGEN+EX_R14(r13); \
- blt masked_interrupt_book3e_##n; \
-1:
+ bne masked_interrupt_book3e_##n
/*
* Additional regs must be re-loaded from paca before EXCEPTION_COMMON* is
diff --git a/arch/powerpc/kernel/interrupt_64.S b/arch/powerpc/kernel/interrupt_64.S
index e7a50613a570..0a8afec6c07b 100644
--- a/arch/powerpc/kernel/interrupt_64.S
+++ b/arch/powerpc/kernel/interrupt_64.S
@@ -196,6 +196,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
RFI_TO_USER
.Lsyscall_vectored_\name\()_rst_end:
+#ifdef CONFIG_PPC_BOOK3S
syscall_vectored_\name\()_restart:
GET_PACA(r13)
ld r1,PACA_EXIT_SAVE_R1(r13)
@@ -209,6 +210,7 @@ syscall_vectored_\name\()_restart:
b .Lsyscall_vectored_\name\()_rst_start
RESTART_TABLE(.Lsyscall_vectored_\name\()_rst_start, .Lsyscall_vectored_\name\()_rst_end, syscall_vectored_\name\()_restart)
+#endif
.endm
@@ -320,10 +322,12 @@ END_BTB_FLUSH_SECTION
li r5,0 /* !scv */
bl syscall_exit_prepare
std r1,PACA_EXIT_SAVE_R1(r13) /* save r1 for restart */
+#ifdef CONFIG_PPC_BOOK3S
.Lsyscall_rst_start:
lbz r11,PACAIRQHAPPENED(r13)
andi. r11,r11,(~PACA_IRQ_HARD_DIS)@l
bne- syscall_restart
+#endif
li r11,IRQS_ENABLED
stb r11,PACAIRQSOFTMASK(r13)
li r11,0
@@ -396,6 +400,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
b .Lsyscall_restore_regs_cont
.Lsyscall_rst_end:
+#ifdef CONFIG_PPC_BOOK3S
syscall_restart:
GET_PACA(r13)
ld r1,PACA_EXIT_SAVE_R1(r13)
@@ -409,6 +414,7 @@ syscall_restart:
b .Lsyscall_rst_start
RESTART_TABLE(.Lsyscall_rst_start, .Lsyscall_rst_end, syscall_restart)
+#endif
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
tabort_syscall:
@@ -504,10 +510,12 @@ _ASM_NOKPROBE_SYMBOL(interrupt_return_\srr\())
bne- .Lrestore_nvgprs_\srr
.Lrestore_nvgprs_\srr\()_cont:
std r1,PACA_EXIT_SAVE_R1(r13) /* save r1 for restart */
+#ifdef CONFIG_PPC_BOOK3S
.Linterrupt_return_\srr\()_user_rst_start:
lbz r11,PACAIRQHAPPENED(r13)
andi. r11,r11,(~PACA_IRQ_HARD_DIS)@l
bne- interrupt_return_\srr\()_user_restart
+#endif
li r11,IRQS_ENABLED
stb r11,PACAIRQSOFTMASK(r13)
li r11,0
@@ -590,6 +598,7 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
REST_NVGPRS(r1)
b .Lrestore_nvgprs_\srr\()_cont
+#ifdef CONFIG_PPC_BOOK3S
interrupt_return_\srr\()_user_restart:
GET_PACA(r13)
ld r1,PACA_EXIT_SAVE_R1(r13)
@@ -602,6 +611,7 @@ interrupt_return_\srr\()_user_restart:
b .Linterrupt_return_\srr\()_user_rst_start
RESTART_TABLE(.Linterrupt_return_\srr\()_user_rst_start, .Linterrupt_return_\srr\()_user_rst_end, interrupt_return_\srr\()_user_restart)
+#endif
.balign IFETCH_ALIGN_BYTES
.Lkernel_interrupt_return_\srr\():
@@ -615,9 +625,11 @@ RESTART_TABLE(.Linterrupt_return_\srr\()_user_rst_start, .Linterrupt_return_\srr
cmpwi r11,IRQS_ENABLED
stb r11,PACAIRQSOFTMASK(r13)
bne 1f
+#ifdef CONFIG_PPC_BOOK3S
lbz r11,PACAIRQHAPPENED(r13)
andi. r11,r11,(~PACA_IRQ_HARD_DIS)@l
bne- interrupt_return_\srr\()_kernel_restart
+#endif
li r11,0
stb r11,PACAIRQHAPPENED(r13) # clear out possible HARD_DIS
1:
@@ -717,6 +729,7 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
b . /* prevent speculative execution */
.Linterrupt_return_\srr\()_kernel_rst_end:
+#ifdef CONFIG_PPC_BOOK3S
interrupt_return_\srr\()_kernel_restart:
GET_PACA(r13)
ld r1,PACA_EXIT_SAVE_R1(r13)
@@ -729,14 +742,15 @@ interrupt_return_\srr\()_kernel_restart:
b .Linterrupt_return_\srr\()_kernel_rst_start
RESTART_TABLE(.Linterrupt_return_\srr\()_kernel_rst_start, .Linterrupt_return_\srr\()_kernel_rst_end, interrupt_return_\srr\()_kernel_restart)
+#endif
.endm
interrupt_return_macro srr
#ifdef CONFIG_PPC_BOOK3S
interrupt_return_macro hsrr
-#endif /* CONFIG_PPC_BOOK3S */
.globl __end_soft_masked
__end_soft_masked:
DEFINE_FIXED_SYMBOL(__end_soft_masked)
+#endif /* CONFIG_PPC_BOOK3S */
--
2.23.0
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