[RFC 07/10] arm64/mm: Detect and enable FEAT_LPA2
From: Anshuman Khandual <hidden>
Date: 2021-07-14 02:21:34
Also in:
linux-arm-kernel, lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
Detect FEAT_LPA2 implementation early enough during boot when requested via CONFIG_ARM64_PA_BITS_52_LPA2 and remember in a variable arm64_lpa2_enabled. This variable could then be used to turn on TCR_EL1.TCR_DS effecting the 52 bits PA range or fall back to default 48 bits PA range if FEAT_LPA2 feature was requested but found not to be implemented. Signed-off-by: Anshuman Khandual <redacted> --- arch/arm64/include/asm/memory.h | 1 + arch/arm64/kernel/head.S | 15 +++++++++++++++ arch/arm64/mm/mmu.c | 3 +++ arch/arm64/mm/proc.S | 9 +++++++++ 4 files changed, 28 insertions(+)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 824a365..d0ca002 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h@@ -178,6 +178,7 @@ #include <asm/bug.h> extern u64 vabits_actual; +extern u64 arm64_lpa2_enabled; 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 6444147..9cf79ea 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S@@ -94,6 +94,21 @@ SYM_CODE_START(primary_entry) adrp x23, __PHYS_OFFSET and x23, x23, MIN_KIMG_ALIGN - 1 // KASLR offset, defaults to 0 bl set_cpu_boot_mode_flag + +#ifdef CONFIG_ARM64_PA_BITS_52_LPA2 + mrs x10, ID_AA64MMFR0_EL1 + ubfx x10, x10, #ID_AA64MMFR0_TGRAN_SHIFT, 4 + cmp x10, #ID_AA64MMFR0_TGRAN_LPA2 + b.ne 1f + + mov x10, #1 + adr_l x11, arm64_lpa2_enabled + str x10, [x11] + dmb sy + dc ivac, x11 +1: +#endif /* CONFIG_ARM64_PA_BITS_52_LPA2 */ + bl __create_page_tables /* * The following calls CPU setup code, see arch/arm64/mm/proc.S for
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index d745865..00b7595 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c@@ -48,6 +48,9 @@ u64 idmap_ptrs_per_pgd = PTRS_PER_PGD; u64 __section(".mmuoff.data.write") vabits_actual; EXPORT_SYMBOL(vabits_actual); +u64 __section(".mmuoff.data.write") arm64_lpa2_enabled; +EXPORT_SYMBOL(arm64_lpa2_enabled); + u64 kimage_voffset __ro_after_init; EXPORT_SYMBOL(kimage_voffset);
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 1ae0c2b..672880c 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S@@ -423,6 +423,15 @@ SYM_FUNC_START(__cpu_setup) TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \ TCR_TBI0 | TCR_A1 | TCR_KASAN_SW_FLAGS +#ifdef CONFIG_ARM64_PA_BITS_52_LPA2 + ldr_l x10, arm64_lpa2_enabled + cmp x10, #1 + b.ne 1f + mov_q x10, TCR_DS + orr tcr, tcr, x10 +1: +#endif /* CONFIG_ARM64_PA_BITS_52_LPA2 */ + #ifdef CONFIG_ARM64_MTE /* * Update MAIR_EL1, GCR_EL1 and TFSR*_EL1 if MTE is supported
--
2.7.4