From: Rohan McLure <rmclure@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Rohan McLure <rmclure@linux.ibm.com>,
Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH v6 05/25] powerpc/32: Clarify interrupt restores with REST_GPR macro in entry_32.S
Date: Wed, 21 Sep 2022 16:55:45 +1000 [thread overview]
Message-ID: <20220921065605.1051927-6-rmclure@linux.ibm.com> (raw)
In-Reply-To: <20220921065605.1051927-1-rmclure@linux.ibm.com>
Restoring the register state of the interrupted thread involves issuing
a large number of predictable loads to the kernel stack frame. Issue the
REST_GPR{,S} macros to clearly signal when this is happening, and bunch
together restores at the end of the interrupt handler where the saved
value is not consumed earlier in the handler code.
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reported-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
---
V3: New patch.
V4: Minimise restores in the unrecoverable window between
restoring SRR0/1 and return from interrupt.
---
arch/powerpc/kernel/entry_32.S | 33 +++++++++++++-------------------
1 file changed, 13 insertions(+), 20 deletions(-)
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 44dfce9a60c5..e4b694cebc44 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -68,7 +68,7 @@ prepare_transfer_to_handler:
lwz r9,_MSR(r11) /* if sleeping, clear MSR.EE */
rlwinm r9,r9,0,~MSR_EE
lwz r12,_LINK(r11) /* and return to address in LR */
- lwz r2, GPR2(r11)
+ REST_GPR(2, r11)
b fast_exception_return
_ASM_NOKPROBE_SYMBOL(prepare_transfer_to_handler)
#endif /* CONFIG_PPC_BOOK3S_32 || CONFIG_E500 */
@@ -144,7 +144,7 @@ ret_from_syscall:
lwz r7,_NIP(r1)
lwz r8,_MSR(r1)
cmpwi r3,0
- lwz r3,GPR3(r1)
+ REST_GPR(3, r1)
syscall_exit_finish:
mtspr SPRN_SRR0,r7
mtspr SPRN_SRR1,r8
@@ -152,8 +152,8 @@ syscall_exit_finish:
bne 3f
mtcr r5
-1: lwz r2,GPR2(r1)
- lwz r1,GPR1(r1)
+1: REST_GPR(2, r1)
+ REST_GPR(1, r1)
rfi
#ifdef CONFIG_40x
b . /* Prevent prefetch past rfi */
@@ -165,10 +165,8 @@ syscall_exit_finish:
REST_NVGPRS(r1)
mtctr r4
mtxer r5
- lwz r0,GPR0(r1)
- lwz r3,GPR3(r1)
- REST_GPRS(4, 11, r1)
- lwz r12,GPR12(r1)
+ REST_GPR(0, r1)
+ REST_GPRS(3, 12, r1)
b 1b
#ifdef CONFIG_44x
@@ -260,9 +258,8 @@ fast_exception_return:
beq 3f /* if not, we've got problems */
#endif
-2: REST_GPRS(3, 6, r11)
- lwz r10,_CCR(r11)
- REST_GPRS(1, 2, r11)
+2: lwz r10,_CCR(r11)
+ REST_GPRS(1, 6, r11)
mtcr r10
lwz r10,_LINK(r11)
mtlr r10
@@ -277,7 +274,7 @@ fast_exception_return:
mtspr SPRN_SRR0,r12
REST_GPR(9, r11)
REST_GPR(12, r11)
- lwz r11,GPR11(r11)
+ REST_GPR(11, r11)
rfi
#ifdef CONFIG_40x
b . /* Prevent prefetch past rfi */
@@ -454,9 +451,8 @@ _ASM_NOKPROBE_SYMBOL(interrupt_return)
lwz r3,_MSR(r1); \
andi. r3,r3,MSR_PR; \
bne interrupt_return; \
- lwz r0,GPR0(r1); \
- lwz r2,GPR2(r1); \
- REST_GPRS(3, 8, r1); \
+ REST_GPR(0, r1); \
+ REST_GPRS(2, 8, r1); \
lwz r10,_XER(r1); \
lwz r11,_CTR(r1); \
mtspr SPRN_XER,r10; \
@@ -475,11 +471,8 @@ _ASM_NOKPROBE_SYMBOL(interrupt_return)
lwz r12,_MSR(r1); \
mtspr exc_lvl_srr0,r11; \
mtspr exc_lvl_srr1,r12; \
- lwz r9,GPR9(r1); \
- lwz r12,GPR12(r1); \
- lwz r10,GPR10(r1); \
- lwz r11,GPR11(r1); \
- lwz r1,GPR1(r1); \
+ REST_GPRS(9, 12, r1); \
+ REST_GPR(1, r1); \
exc_lvl_rfi; \
b .; /* prevent prefetch past exc_lvl_rfi */
--
2.34.1
next prev parent reply other threads:[~2022-09-21 7:01 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-21 6:55 [PATCH v6 00/25] powerpc: Syscall wrapper and register clearing Rohan McLure
2022-09-21 6:55 ` [PATCH v6 01/25] powerpc: Remove asmlinkage from syscall handler definitions Rohan McLure
2022-09-21 6:55 ` [PATCH v6 02/25] powerpc: Save caller r3 prior to system_call_exception Rohan McLure
2022-09-21 6:55 ` [PATCH v6 03/25] powerpc: Add ZEROIZE_GPRS macros for register clears Rohan McLure
2022-09-21 6:55 ` [PATCH v6 04/25] powerpc/64s: Use {ZEROIZE,SAVE,REST}_GPRS macros in sc, scv 0 handlers Rohan McLure
2022-09-21 6:55 ` Rohan McLure [this message]
2022-09-21 6:55 ` [PATCH v6 06/25] powerpc/64e: Clarify register saves and clears with {SAVE,ZEROIZE}_GPRS Rohan McLure
2022-09-21 6:55 ` [PATCH v6 07/25] powerpc/64s: Fix comment on interrupt handler prologue Rohan McLure
2022-09-21 6:55 ` [PATCH v6 08/25] powerpc: Fix fallocate and fadvise64_64 compat parameter combination Rohan McLure
2022-09-21 6:55 ` [PATCH v6 09/25] asm-generic: compat: Support BE for long long args in 32-bit ABIs Rohan McLure
2022-10-31 13:23 ` [PATCH] asm-generic: compat: fix compat_arg_u64 and compat_arg_u64_dual Andreas Schwab
2022-11-01 12:25 ` Michael Ellerman
2022-11-03 8:20 ` Christophe Leroy
2022-11-03 8:48 ` Arnd Bergmann
2022-09-21 6:55 ` [PATCH v6 10/25] powerpc: Use generic fallocate compatibility syscall Rohan McLure
2022-09-21 6:55 ` [PATCH v6 11/25] powerpc/32: Remove powerpc select specialisation Rohan McLure
2022-09-21 6:55 ` [PATCH v6 12/25] powerpc: Remove direct call to personality syscall handler Rohan McLure
2022-09-21 6:55 ` [PATCH v6 13/25] powerpc: Remove direct call to mmap2 syscall handlers Rohan McLure
2022-09-28 12:15 ` Michael Ellerman
2022-09-28 13:00 ` Arnd Bergmann
2022-09-30 13:19 ` Michael Ellerman
2022-09-30 14:09 ` Arnd Bergmann
2022-09-21 6:55 ` [PATCH v6 14/25] powerpc: Provide do_ppc64_personality helper Rohan McLure
2022-09-21 6:55 ` [PATCH v6 15/25] powerpc: Adopt SYSCALL_DEFINE for arch-specific syscall handlers Rohan McLure
2022-09-21 6:55 ` [PATCH v6 16/25] powerpc: Include all arch-specific syscall prototypes Rohan McLure
2022-09-21 6:55 ` [PATCH v6 17/25] powerpc: Enable compile-time check for syscall handlers Rohan McLure
2022-09-21 6:55 ` [PATCH v6 18/25] powerpc: Use common syscall handler type Rohan McLure
2022-09-21 6:55 ` [PATCH v6 19/25] powerpc: Remove high-order word clearing on compat syscall entry Rohan McLure
2022-09-23 7:40 ` Nicholas Piggin
2022-09-28 11:56 ` Michael Ellerman
2022-09-21 6:56 ` [PATCH v6 20/25] powerpc: Change system_call_exception calling convention Rohan McLure
2022-09-23 7:43 ` Nicholas Piggin
2022-09-21 6:56 ` [PATCH v6 21/25] powerpc: Provide syscall wrapper Rohan McLure
2022-09-23 7:50 ` Nicholas Piggin
2022-10-30 15:34 ` Andreas Schwab
2022-10-30 15:50 ` Andreas Schwab
2022-10-30 19:43 ` Arnd Bergmann
2022-10-30 20:05 ` Andreas Schwab
2022-10-31 3:09 ` Michael Ellerman
2022-10-31 14:47 ` [PATCH] powerpc/32: fix syscall wrappers with 64-bit arguments Andreas Schwab
2022-10-31 19:37 ` Arnd Bergmann
2022-11-01 12:25 ` Michael Ellerman
2022-09-21 6:56 ` [PATCH v6 22/25] powerpc/64s: Clear user GPRs in syscall interrupt entry Rohan McLure
2022-09-23 8:02 ` Nicholas Piggin
2022-10-31 23:22 ` Rohan McLure
2022-09-21 6:56 ` [PATCH v6 23/25] powerpc/64: Add INTERRUPT_SANITIZE_REGISTERS Kconfig Rohan McLure
2022-09-21 6:56 ` [PATCH v6 24/25] powerpc/64s: Clear gprs on interrupt routine entry in Book3S Rohan McLure
2022-09-21 6:56 ` [PATCH v6 25/25] powerpc/64e: Clear gprs on interrupt routine entry on Book3E Rohan McLure
2022-10-04 13:24 ` [PATCH v6 00/25] powerpc: Syscall wrapper and register clearing Michael Ellerman
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