[PATCH 1/2] powerpc/64: Correct comment on LOAD_HANDLER()

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

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6 messages, 3 authors, 2016-09-13 · open the first message on its own page

[PATCH 1/2] powerpc/64: Correct comment on LOAD_HANDLER()

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2016-07-26 05:29:35

The comment for LOAD_HANDLER() was wrong. The part about kdump has not
been true since 1f6a93e4c35e ("powerpc: Make it possible to move the
interrupt handlers away from the kernel").

Describe how it currently works, and combine the two separate comments
into one.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/include/asm/exception-64s.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 93ae809fe5ea..4ff3e2f16b5d 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h

@@ -84,12 +84,12 @@
 
 /*
  * We're short on space and time in the exception prolog, so we can't
- * use the normal SET_REG_IMMEDIATE macro. Normally we just need the
- * low halfword of the address, but for Kdump we need the whole low
- * word.
+ * use the normal LOAD_REG_IMMEDIATE macro to load the address of label.
+ * Instead we get the base of the kernel from paca->kernelbase and or in the low
+ * part of label. This requires that the label be within 64KB of kernelbase, and
+ * that kernelbase be 64K aligned.
  */
 #define LOAD_HANDLER(reg, label)					\
-	/* Handlers must be within 64K of kbase, which must be 64k aligned */ \
 	ori	reg,reg,(label)-_stext;	/* virt addr of handler ... */
 
 /* Exception register prefixes */

-- 
2.7.4

[PATCH 2/2] powerpc/64: Do load of PACAKBASE in LOAD_HANDLER

From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2016-07-26 05:29:35

The LOAD_HANDLER macro requires that you have previously loaded "reg"
with PACAKBASE. Although that gives callers flexibility to get PACAKBASE
in some interesting way, none of the callers actually do that. So fold
the load of PACAKBASE into the macro, making it simpler for callers to
use correctly.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/include/asm/exception-64s.h |  3 +--
 arch/powerpc/kernel/exceptions-64s.S     | 10 ----------
 2 files changed, 1 insertion(+), 12 deletions(-)

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 4ff3e2f16b5d..887867ac4bfa 100644
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h

@@ -52,7 +52,6 @@
 
 #ifdef CONFIG_RELOCATABLE
 #define __EXCEPTION_RELON_PROLOG_PSERIES_1(label, h)			\
-	ld	r12,PACAKBASE(r13);	/* get high part of &label */	\
 	mfspr	r11,SPRN_##h##SRR0;	/* save SRR0 */			\
 	LOAD_HANDLER(r12,label);					\
 	mtctr	r12;							\

@@ -90,6 +89,7 @@
  * that kernelbase be 64K aligned.
  */
 #define LOAD_HANDLER(reg, label)					\
+	ld	reg,PACAKBASE(r13);	/* get high part of &label */	\
 	ori	reg,reg,(label)-_stext;	/* virt addr of handler ... */
 
 /* Exception register prefixes */

@@ -175,7 +175,6 @@ END_FTR_SECTION_NESTED(ftr,ftr,943)
 	__EXCEPTION_PROLOG_1(area, extra, vec)
 
 #define __EXCEPTION_PROLOG_PSERIES_1(label, h)				\
-	ld	r12,PACAKBASE(r13);	/* get high part of &label */	\
 	ld	r10,PACAKMSR(r13);	/* get MSR value for kernel */	\
 	mfspr	r11,SPRN_##h##SRR0;	/* save SRR0 */			\
 	LOAD_HANDLER(r12,label)						\

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 8bcc1b457115..af30f26c35d8 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S

@@ -41,7 +41,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_REAL_LE)				\
 
 #define SYSCALL_PSERIES_2_RFID 					\
 	mfspr	r12,SPRN_SRR1 ;					\
-	ld	r10,PACAKBASE(r13) ; 				\
 	LOAD_HANDLER(r10, system_call_entry) ; 			\
 	mtspr	SPRN_SRR0,r10 ; 				\
 	ld	r10,PACAKMSR(r13) ;				\

@@ -64,7 +63,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_REAL_LE)				\
 	 */
 #define SYSCALL_PSERIES_2_DIRECT				\
 	mflr	r10 ;						\
-	ld	r12,PACAKBASE(r13) ; 				\
 	LOAD_HANDLER(r12, system_call_entry) ;			\
 	mtctr	r12 ;						\
 	mfspr	r12,SPRN_SRR1 ;					\

@@ -219,7 +217,6 @@ data_access_slb_pSeries:
 	 * the kernel ends up being put.
 	 */
 	mfctr	r11
-	ld	r10,PACAKBASE(r13)
 	LOAD_HANDLER(r10, slb_miss_realmode)
 	mtctr	r10
 	bctr

@@ -240,7 +237,6 @@ instruction_access_slb_pSeries:
 	b	slb_miss_realmode
 #else
 	mfctr	r11
-	ld	r10,PACAKBASE(r13)
 	LOAD_HANDLER(r10, slb_miss_realmode)
 	mtctr	r10
 	bctr

@@ -486,7 +482,6 @@ BEGIN_FTR_SECTION
 	mfmsr	r11			/* get MSR value */
 	ori	r11,r11,MSR_ME		/* turn on ME bit */
 	ori	r11,r11,MSR_RI		/* turn on RI bit */
-	ld	r12,PACAKBASE(r13)	/* get high part of &label */
 	LOAD_HANDLER(r12, machine_check_handle_early)
 1:	mtspr	SPRN_SRR0,r12
 	mtspr	SPRN_SRR1,r11

@@ -499,7 +494,6 @@ BEGIN_FTR_SECTION
 	 */
 	addi	r1,r1,INT_FRAME_SIZE	/* go back to previous stack frame */
 	ld	r11,PACAKMSR(r13)
-	ld	r12,PACAKBASE(r13)
 	LOAD_HANDLER(r12, unrecover_mce)
 	li	r10,MSR_ME
 	andc	r11,r11,r10		/* Turn off MSR_ME */

@@ -802,7 +796,6 @@ data_access_slb_relon_pSeries:
 	 * the kernel ends up being put.
 	 */
 	mfctr	r11
-	ld	r10,PACAKBASE(r13)
 	LOAD_HANDLER(r10, slb_miss_realmode)
 	mtctr	r10
 	bctr

@@ -822,7 +815,6 @@ instruction_access_slb_relon_pSeries:
 	b	slb_miss_realmode
 #else
 	mfctr	r11
-	ld	r10,PACAKBASE(r13)
 	LOAD_HANDLER(r10, slb_miss_realmode)
 	mtctr	r10
 	bctr

@@ -1321,7 +1313,6 @@ machine_check_handle_early:
 	andi.	r11,r12,MSR_RI
 	bne	2f
 1:	mfspr	r11,SPRN_SRR0
-	ld	r10,PACAKBASE(r13)
 	LOAD_HANDLER(r10,unrecover_mce)
 	mtspr	SPRN_SRR0,r10
 	ld	r10,PACAKMSR(r13)

@@ -1422,7 +1413,6 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_RADIX)
 	b	.	/* prevent speculative execution */
 
 2:	mfspr	r11,SPRN_SRR0
-	ld	r10,PACAKBASE(r13)
 	LOAD_HANDLER(r10,unrecov_slb)
 	mtspr	SPRN_SRR0,r10
 	ld	r10,PACAKMSR(r13)

-- 
2.7.4

Re: [PATCH 2/2] powerpc/64: Do load of PACAKBASE in LOAD_HANDLER

From: Nicholas Piggin <npiggin@gmail.com>
Date: 2016-07-26 06:36:42

On Tue, 26 Jul 2016 15:29:30 +1000
Michael Ellerman [off-list ref] wrote:

The LOAD_HANDLER macro requires that you have previously loaded "reg"
with PACAKBASE. Although that gives callers flexibility to get
PACAKBASE in some interesting way, none of the callers actually do
that. So fold the load of PACAKBASE into the macro, making it simpler
for callers to use correctly.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

I don't see any problem with this.

Reviewed-by: Nick Piggin <npiggin@gmail.com>

Re: [2/2] powerpc/64: Do load of PACAKBASE in LOAD_HANDLER

From: Michael Ellerman <hidden>
Date: 2016-09-13 12:16:29

On Tue, 2016-26-07 at 05:29:30 UTC, Michael Ellerman wrote:

The LOAD_HANDLER macro requires that you have previously loaded "reg"
with PACAKBASE. Although that gives callers flexibility to get PACAKBASE
in some interesting way, none of the callers actually do that. So fold
the load of PACAKBASE into the macro, making it simpler for callers to
use correctly.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nick Piggin <npiggin@gmail.com>

Applied to powerpc next.

https://git.kernel.org/powerpc/c/d8d42b0511fefc78165ee9b4c2

cheers

Re: [PATCH 1/2] powerpc/64: Correct comment on LOAD_HANDLER()

From: Nicholas Piggin <npiggin@gmail.com>
Date: 2016-07-26 06:17:15

On Tue, 26 Jul 2016 15:29:29 +1000
Michael Ellerman [off-list ref] wrote:

The comment for LOAD_HANDLER() was wrong. The part about kdump has not
been true since 1f6a93e4c35e ("powerpc: Make it possible to move the
interrupt handlers away from the kernel").

Describe how it currently works, and combine the two separate comments
into one.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Reviewed-by: Nick Piggin <npiggin@gmail.com>

quoted hunk

---
 arch/powerpc/include/asm/exception-64s.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/exception-64s.h

b/arch/powerpc/include/asm/exception-64s.h index
93ae809fe5ea..4ff3e2f16b5d 100644 ---
a/arch/powerpc/include/asm/exception-64s.h +++
b/arch/powerpc/include/asm/exception-64s.h @@ -84,12 +84,12 @@
 
 /*
  * We're short on space and time in the exception prolog, so we can't
- * use the normal SET_REG_IMMEDIATE macro. Normally we just need the
- * low halfword of the address, but for Kdump we need the whole low
- * word.
+ * use the normal LOAD_REG_IMMEDIATE macro to load the address of
label.
+ * Instead we get the base of the kernel from paca->kernelbase and
or in the low
+ * part of label. This requires that the label be within 64KB of
kernelbase, and
+ * that kernelbase be 64K aligned.
  */
 #define LOAD_HANDLER(reg,
label)					\
-	/* Handlers must be within 64K of kbase, which must be 64k
aligned */ \ ori	reg,reg,(label)-_stext;	/* virt addr
of handler ... */ 
 /* Exception register prefixes */

Re: [1/2] powerpc/64: Correct comment on LOAD_HANDLER()

From: Michael Ellerman <hidden>
Date: 2016-09-13 12:16:24

On Tue, 2016-26-07 at 05:29:29 UTC, Michael Ellerman wrote:

The comment for LOAD_HANDLER() was wrong. The part about kdump has not
been true since 1f6a93e4c35e ("powerpc: Make it possible to move the
interrupt handlers away from the kernel").

Describe how it currently works, and combine the two separate comments
into one.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nick Piggin <npiggin@gmail.com>

Applied to powerpc next.

https://git.kernel.org/powerpc/c/27510235dd2bb1ab01d27b01f0

cheers

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