diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2022-06-24 17:06:32 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2022-06-24 17:18:09 +0100 |
| commit | 0d9b1ffefabee93727bae68201593fac80a79002 (patch) | |
| tree | 8c0b7a0645e617ca07c18f2c5ccde862fdf3c794 | |
| parent | 475031b6ed43d208925c81bea612f48c3259c3c8 (diff) | |
| download | linux-0d9b1ffefabee93727bae68201593fac80a79002.tar.bz2 | |
arm64: mm: make vabits_actual a build time constant if possible
Currently, we only support 52-bit virtual addressing on 64k pages
configurations, and in all other cases, vabits_actual is guaranteed to
equal VA_BITS (== VA_BITS_MIN). So get rid of the variable entirely in
that case.
While at it, move the assignment out of the asm entry code - it has no
need to be there.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20220624150651.1358849-3-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | arch/arm64/include/asm/memory.h | 4 | ||||
| -rw-r--r-- | arch/arm64/kernel/head.S | 15 | ||||
| -rw-r--r-- | arch/arm64/mm/init.c | 15 | ||||
| -rw-r--r-- | arch/arm64/mm/mmu.c | 4 |
4 files changed, 22 insertions, 16 deletions
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 0af70d9abede..c751cd9b94f8 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -174,7 +174,11 @@ #include <linux/types.h> #include <asm/bug.h> +#if VA_BITS > 48 extern u64 vabits_actual; +#else +#define vabits_actual ((u64)VA_BITS) +#endif extern s64 memstart_addr; /* PHYS_OFFSET - the physical address of the start of memory. */ diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 1cdecce552bb..dc07858eb673 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -293,19 +293,6 @@ SYM_FUNC_START_LOCAL(__create_page_tables) adrp x0, idmap_pg_dir adrp x3, __idmap_text_start // __pa(__idmap_text_start) -#ifdef CONFIG_ARM64_VA_BITS_52 - mrs_s x6, SYS_ID_AA64MMFR2_EL1 - and x6, x6, #(0xf << ID_AA64MMFR2_LVA_SHIFT) - mov x5, #52 - cbnz x6, 1f -#endif - mov x5, #VA_BITS_MIN -1: - adr_l x6, vabits_actual - str x5, [x6] - dmb sy - dc ivac, x6 // Invalidate potentially stale cache line - /* * VA_BITS may be too small to allow for an ID mapping to be created * that covers system RAM if that is located sufficiently high in the @@ -713,7 +700,7 @@ SYM_FUNC_START(__enable_mmu) SYM_FUNC_END(__enable_mmu) SYM_FUNC_START(__cpu_secondary_check52bitva) -#ifdef CONFIG_ARM64_VA_BITS_52 +#if VA_BITS > 48 ldr_l x0, vabits_actual cmp x0, #52 b.ne 2f diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 339ee84e5a61..1faa6760895e 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -265,7 +265,20 @@ early_param("mem", early_mem); void __init arm64_memblock_init(void) { - s64 linear_region_size = PAGE_END - _PAGE_OFFSET(vabits_actual); + s64 linear_region_size; + +#if VA_BITS > 48 + if (cpuid_feature_extract_unsigned_field( + read_sysreg_s(SYS_ID_AA64MMFR2_EL1), + ID_AA64MMFR2_LVA_SHIFT)) + vabits_actual = VA_BITS; + + /* make the variable visible to secondaries with the MMU off */ + dcache_clean_inval_poc((u64)&vabits_actual, + (u64)&vabits_actual + sizeof(vabits_actual)); +#endif + + linear_region_size = PAGE_END - _PAGE_OFFSET(vabits_actual); /* * Corner case: 52-bit VA capable systems running KVM in nVHE mode may diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index fde2b326419a..88b4177254a0 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -46,8 +46,10 @@ u64 idmap_t0sz = TCR_T0SZ(VA_BITS_MIN); u64 idmap_ptrs_per_pgd = PTRS_PER_PGD; -u64 __section(".mmuoff.data.write") vabits_actual; +#if VA_BITS > 48 +u64 vabits_actual __ro_after_init = VA_BITS_MIN; EXPORT_SYMBOL(vabits_actual); +#endif u64 kimage_vaddr __ro_after_init = (u64)&_text; EXPORT_SYMBOL(kimage_vaddr); |