[PATCH v5 14/18] powerpc/e500: Free r10 for FIND_PTE

Christophe Leroy
2024-06-10T05:56:05Z

Move r13 load after the call to FIND_PTE, and use r13 instead of
r10 for storing fault address. This will allow using r10 freely
in FIND_PTE in following patch to handle hugepage size.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
v5: New
---
arch/powerpc/kernel/head_85xx.S | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/kernel/head_85xx.S b/arch/powerpc/kernel/head_85xx.S
index 282e49c51deb..226f88e77d6d 100644
--- a/arch/powerpc/kernel/head_85xx.S
+++ b/arch/powerpc/kernel/head_85xx.S
@@ -294,9 +294,10 @@ set_ivor:
/* Macros to hide the PTE size differences
*
* FIND_PTE -- walks the page tables given EA & pgdir pointer
- * r10 -- EA of fault
+ * r10 -- free
* r11 -- PGDIR pointer
* r12 -- free
+ * r13 -- EA of fault
* label 2: is the bailout case
*
* if we find the pte (fall through):
@@ -307,7 +308,7 @@ set_ivor:
#ifdef CONFIG_PTE_64BIT
#ifdef CONFIG_HUGETLB_PAGE
#define FIND_PTE \
- rlwinm r12, r10, 14, 18, 28; /* Compute pgdir/pmd offset */ \
+ rlwinm r12, r13, 14, 18, 28; /* Compute pgdir/pmd offset */ \
add r12, r11, r12; \
lwz r11, 4(r12); /* Get pgd/pmd entry */ \
rlwinm. r12, r11, 0, 0, 20; /* Extract pt base address */ \
@@ -317,26 +318,26 @@ set_ivor:
andi. r10, r11, HUGEPD_SHIFT_MASK@l; /* extract size field */ \
xor r12, r10, r11; /* drop size bits from pointer */ \
b 1001f; \
-1000: rlwimi r12, r10, 23, 20, 28; /* Compute pte address */ \
+1000: rlwimi r12, r13, 23, 20, 28; /* Compute pte address */ \
li r10, 0; /* clear r10 */ \
1001: lwz r11, 4(r12); /* Get pte entry */
#else
#define FIND_PTE \
- rlwinm r12, r10, 14, 18, 28; /* Compute pgdir/pmd offset */ \
+ rlwinm r12, r13, 14, 18, 28; /* Compute pgdir/pmd offset */ \
add r12, r11, r12; \
lwz r11, 4(r12); /* Get pgd/pmd entry */ \
rlwinm. r12, r11, 0, 0, 20; /* Extract pt base address */ \
beq 2f; /* Bail if no table */ \
- rlwimi r12, r10, 23, 20, 28; /* Compute pte address */ \
+ rlwimi r12, r13, 23, 20, 28; /* Compute pte address */ \
lwz r11, 4(r12); /* Get pte entry */
#endif /* HUGEPAGE */
#else /* !PTE_64BIT */
#define FIND_PTE \
- rlwimi r11, r10, 12, 20, 29; /* Create L1 (pgdir/pmd) address */ \
+ rlwimi r11, r13, 12, 20, 29; /* Create L1 (pgdir/pmd) address */ \
lwz r11, 0(r11); /* Get L1 entry */ \
rlwinm. r12, r11, 0, 0, 19; /* Extract L2 (pte) base address */ \
beq 2f; /* Bail if no table */ \
- rlwimi r12, r10, 22, 20, 29; /* Compute PTE address */ \
+ rlwimi r12, r13, 22, 20, 29; /* Compute PTE address */ \
lwz r11, 0(r12); /* Get Linux PTE */
#endif

@@ -443,13 +444,13 @@ START_BTB_FLUSH_SECTION
BTB_FLUSH(r10)
1:
END_BTB_FLUSH_SECTION
- mfspr r10, SPRN_DEAR /* Get faulting address */
+ mfspr r13, SPRN_DEAR /* Get faulting address */

/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
lis r11, PAGE_OFFSET@h
- cmplw 5, r10, r11
+ cmplw 5, r13, r11
blt 5, 3f
lis r11, swapper_pg_dir@h
ori r11, r11, swapper_pg_dir@l
@@ -472,14 +473,14 @@ END_BTB_FLUSH_SECTION
#endif

4:
+ FIND_PTE
+
#ifdef CONFIG_PTE_64BIT
li r13,_PAGE_PRESENT|_PAGE_BAP_SR
oris r13,r13,_PAGE_ACCESSED@h
#else
li r13,_PAGE_PRESENT|_PAGE_READ|_PAGE_ACCESSED
#endif
-
- FIND_PTE
andc. r13,r13,r11 /* Check permission */

#ifdef CONFIG_PTE_64BIT
@@ -536,13 +537,13 @@ START_BTB_FLUSH_SECTION
1:
END_BTB_FLUSH_SECTION

- mfspr r10, SPRN_SRR0 /* Get faulting address */
+ mfspr r13, SPRN_SRR0 /* Get faulting address */

/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
lis r11, PAGE_OFFSET@h
- cmplw 5, r10, r11
+ cmplw 5, r13, r11
blt 5, 3f
lis r11, swapper_pg_dir@h
ori r11, r11, swapper_pg_dir@l
@@ -551,6 +552,7 @@ END_BTB_FLUSH_SECTION
rlwinm r12,r12,0,16,1
mtspr SPRN_MAS1,r12

+ FIND_PTE
/* Make up the required permissions for kernel code */
#ifdef CONFIG_PTE_64BIT
li r13,_PAGE_PRESENT | _PAGE_BAP_SX
@@ -571,6 +573,7 @@ END_BTB_FLUSH_SECTION
beq 2f /* KUAP fault */
#endif

+ FIND_PTE
/* Make up the required permissions for user code */
#ifdef CONFIG_PTE_64BIT
li r13,_PAGE_PRESENT | _PAGE_BAP_UX
@@ -580,7 +583,6 @@ END_BTB_FLUSH_SECTION
#endif

4:
- FIND_PTE
andc. r13,r13,r11 /* Check permission */

#ifdef CONFIG_PTE_64BIT
--
2.44.0