diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2024-08-20 19:23:48 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2024-08-30 21:29:52 +1000 |
| commit | 1a736d98c84acd38e40fff69528ce7aaa55dd22d (patch) | |
| tree | 6b2002f327586ae35bbf94c14d0e1a3b39360ce4 | |
| parent | 985db026c34dfc45213649023d5505822a5dcd78 (diff) | |
Revert "powerpc/8xx: Always pin kernel text TLB"
This reverts commit bccc58986a2f98e3af349c85c5f49aac7fb19ef2.
When STRICT_KERNEL_RWX is selected, EXEC memory must stop where
RW memory start. When pinning iTLBs it means an 8M alignment for
RW data start. That may be acceptable on boards with a lot of
memory but one of my supported boards only has 32 Mbytes and this
forced alignment leads to a waste of almost 4 Mbytes with is more
than 10% of the total memory.
So revert commit bccc58986a2f ("powerpc/8xx: Always pin kernel text
TLB") but don't restore previous behaviour in ITLB miss handler
as now kernel PGD entries are copied into each process PGDIR.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/01b6780b860c8043b51a1ba9d83acfc6f2dde910.1724173828.git.christophe.leroy@csgroup.eu
| -rw-r--r-- | arch/powerpc/kernel/head_8xx.S | 8 | ||||
| -rw-r--r-- | arch/powerpc/mm/nohash/8xx.c | 3 | ||||
| -rw-r--r-- | arch/powerpc/platforms/8xx/Kconfig | 7 |
3 files changed, 17 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index c955a8196d55..66ee0a31d99d 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -587,6 +587,10 @@ start_here: lis r0, (MD_TWAM | MD_RSV4I)@h mtspr SPRN_MD_CTR, r0 #endif +#ifndef CONFIG_PIN_TLB_TEXT + li r0, 0 + mtspr SPRN_MI_CTR, r0 +#endif #if !defined(CONFIG_PIN_TLB_DATA) && !defined(CONFIG_PIN_TLB_IMMR) lis r0, MD_TWAM@h mtspr SPRN_MD_CTR, r0 @@ -683,6 +687,7 @@ SYM_FUNC_START_LOCAL(initial_mmu) blr SYM_FUNC_END(initial_mmu) +#ifdef CONFIG_PIN_TLB _GLOBAL(mmu_pin_tlb) lis r9, (1f - PAGE_OFFSET)@h ori r9, r9, (1f - PAGE_OFFSET)@l @@ -704,6 +709,7 @@ _GLOBAL(mmu_pin_tlb) mtspr SPRN_MD_CTR, r6 tlbia +#ifdef CONFIG_PIN_TLB_TEXT LOAD_REG_IMMEDIATE(r5, 28 << 8) LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET) LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG | _PMD_ACCESSED) @@ -724,6 +730,7 @@ _GLOBAL(mmu_pin_tlb) bdnzt lt, 2b lis r0, MI_RSV4I@h mtspr SPRN_MI_CTR, r0 +#endif LOAD_REG_IMMEDIATE(r5, 28 << 8 | MD_TWAM) #ifdef CONFIG_PIN_TLB_DATA @@ -783,3 +790,4 @@ _GLOBAL(mmu_pin_tlb) mtspr SPRN_SRR1, r10 mtspr SPRN_SRR0, r11 rfi +#endif diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c index 15d918dce27d..4c2f9d716993 100644 --- a/arch/powerpc/mm/nohash/8xx.c +++ b/arch/powerpc/mm/nohash/8xx.c @@ -177,7 +177,8 @@ int mmu_mark_initmem_nx(void) if (!debug_pagealloc_enabled_or_kfence()) err = mmu_mapin_ram_chunk(boundary, einittext8, PAGE_KERNEL, false); - mmu_pin_tlb(block_mapped_ram, false); + if (IS_ENABLED(CONFIG_PIN_TLB_TEXT)) + mmu_pin_tlb(block_mapped_ram, false); return err; } diff --git a/arch/powerpc/platforms/8xx/Kconfig b/arch/powerpc/platforms/8xx/Kconfig index a14d9d8997a4..8623aebfac48 100644 --- a/arch/powerpc/platforms/8xx/Kconfig +++ b/arch/powerpc/platforms/8xx/Kconfig @@ -195,6 +195,13 @@ config PIN_TLB_IMMR CONFIG_PIN_TLB_DATA is also selected, it will reduce CONFIG_PIN_TLB_DATA to 24 Mbytes. +config PIN_TLB_TEXT + bool "Pinned TLB for TEXT" + depends on PIN_TLB + default y + help + This pins kernel text with 8M pages. + endmenu endmenu |