Re: [PATCH 6.10 000/809] 6.10.3-rc3 review
From: Guenter Roeck
Date: Thu Aug 08 2024 - 20:57:09 EST
On 8/8/24 15:29, John David Anglin wrote:
On 2024-08-08 5:50 p.m., John David Anglin wrote:
The mode likely problem is the shladd instruction in the following macro in entry.S:
.macro L2_ptep pmd,pte,index,va,fault
#if CONFIG_PGTABLE_LEVELS == 3
extru_safe \va,31-ASM_PMD_SHIFT,ASM_BITS_PER_PMD,\index
#else
extru_safe \va,31-ASM_PGDIR_SHIFT,ASM_BITS_PER_PGD,\index
#endif
dep %r0,31,PAGE_SHIFT,\pmd /* clear offset */
#if CONFIG_PGTABLE_LEVELS < 3
copy %r0,\pte
#endif
ldw,s \index(\pmd),\pmd
bb,>=,n \pmd,_PxD_PRESENT_BIT,\fault
dep %r0,31,PxD_FLAG_SHIFT,\pmd /* clear flags */
SHLREG \pmd,PxD_VALUE_SHIFT,\pmd
extru_safe \va,31-PAGE_SHIFT,ASM_BITS_PER_PTE,\index
dep %r0,31,PAGE_SHIFT,\pmd /* clear offset */
shladd \index,BITS_PER_PTE_ENTRY,\pmd,\pmd /* pmd is now pte */
.endm
I believe the shladd instruction should be changed to shladd,l (shift left and add logical).
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index ab23e61a6f01..1ec60406f841 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -399,7 +399,7 @@
SHLREG \pmd,PxD_VALUE_SHIFT,\pmd
extru_safe \va,31-PAGE_SHIFT,ASM_BITS_PER_PTE,\index
dep %r0,31,PAGE_SHIFT,\pmd /* clear offset */
- shladd \index,BITS_PER_PTE_ENTRY,\pmd,\pmd /* pmd is now pte */
+ shladd,l \index,BITS_PER_PTE_ENTRY,\pmd,\pmd /* pmd is now pte */
.endm
/* Look up PTE in a 3-Level scheme. */
Boots okay. Fixing the addi instruction is harder and it would take some time to test.
Odd, it doesn't help for me. Does it crash for you without the above change ?
Or, in other words, is divI at the objecting location ?
Guenter