From: Rohan McLure <rmclure@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Rohan McLure <rmclure@linux.ibm.com>
Subject: [PATCH v4 16/20] powerpc/32: Clarify interrupt restores with REST_GPR macro in entry_32.S
Date: Wed, 24 Aug 2022 12:05:44 +1000 [thread overview]
Message-ID: <20220824020548.62625-17-rmclure@linux.ibm.com> (raw)
In-Reply-To: <20220824020548.62625-1-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>
---
V2 -> V3: New patch.
V3 -> 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 8d6e02ef5dc0..963d646915fe 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:[~2022-08-24 2:17 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-24 2:05 [PATCH v4 00/20] powerpc: Syscall wrapper and register clearing Rohan McLure
2022-08-24 2:05 ` [PATCH v4 01/20] powerpc: Remove asmlinkage from syscall handler definitions Rohan McLure
2022-08-25 7:04 ` Andrew Donnellan
2022-09-12 8:20 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 02/20] powerpc: Use generic fallocate compatibility syscall Rohan McLure
2022-09-12 8:38 ` Nicholas Piggin
2022-09-12 9:57 ` Arnd Bergmann
2022-09-12 11:00 ` Christophe Leroy
2022-09-12 11:07 ` Arnd Bergmann
2022-08-24 2:05 ` [PATCH v4 03/20] powerpc/32: Remove powerpc select specialisation Rohan McLure
2022-09-12 9:03 ` Nicholas Piggin
2022-09-15 4:36 ` Rohan McLure
2022-08-24 2:05 ` [PATCH v4 04/20] powerpc: Provide do_ppc64_personality helper Rohan McLure
2022-09-12 9:26 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 05/20] powerpc: Remove direct call to personality syscall handler Rohan McLure
2022-09-12 9:42 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 06/20] powerpc: Remove direct call to mmap2 syscall handlers Rohan McLure
2022-09-12 9:47 ` Nicholas Piggin
2022-09-15 5:06 ` Rohan McLure
2022-08-24 2:05 ` [PATCH v4 07/20] powerpc: Adopt SYSCALL_DEFINE for arch-specific " Rohan McLure
2022-09-12 10:04 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 08/20] powerpc: Include all arch-specific syscall prototypes Rohan McLure
2022-09-12 10:33 ` Nicholas Piggin
2022-09-13 7:09 ` Rohan McLure
2022-08-24 2:05 ` [PATCH v4 09/20] powerpc: Enable compile-time check for syscall handlers Rohan McLure
2022-09-12 10:42 ` Nicholas Piggin
2022-09-13 2:29 ` Michael Ellerman
2022-08-24 2:05 ` [PATCH v4 10/20] powerpc: Use common syscall handler type Rohan McLure
2022-09-12 10:56 ` Nicholas Piggin
2022-09-15 5:45 ` Rohan McLure
2022-09-16 1:02 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 11/20] powerpc: Add ZEROIZE_GPRS macros for register clears Rohan McLure
2022-09-12 11:09 ` Nicholas Piggin
2022-09-15 5:47 ` Rohan McLure
2022-08-24 2:05 ` [PATCH v4 12/20] Revert "powerpc/syscall: Save r3 in regs->orig_r3" Rohan McLure
2022-09-12 11:14 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 13/20] powerpc: Provide syscall wrapper Rohan McLure
2022-09-12 11:26 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 14/20] powerpc/64s: Clear/restore caller gprs in syscall interrupt/return Rohan McLure
2022-09-12 11:47 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 15/20] powerpc/64s: Use {ZEROIZE,SAVE,REST}_GPRS macros in sc, scv 0 handlers Rohan McLure
2022-09-12 11:49 ` Nicholas Piggin
2022-08-24 2:05 ` Rohan McLure [this message]
2022-08-24 2:05 ` [PATCH v4 17/20] powerpc/64e: Clarify register saves and clears with {SAVE,ZEROIZE}_GPRS Rohan McLure
2022-09-12 12:17 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 18/20] powerpc/64s: Fix comment on interrupt handler prologue Rohan McLure
2022-09-12 11:51 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 19/20] powerpc/64s: Clear gprs on interrupt routine entry in Book3S Rohan McLure
2022-09-12 12:15 ` Nicholas Piggin
2022-09-15 6:55 ` Rohan McLure
2022-09-16 0:43 ` Nicholas Piggin
2022-08-24 2:05 ` [PATCH v4 20/20] powerpc/64e: Clear gprs on interrupt routine entry Rohan McLure
2022-09-12 0:55 ` [PATCH v4 00/20] powerpc: Syscall wrapper and register clearing Rohan McLure
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