diff options
| author | Pasha Tatashin <pasha.tatashin@soleen.com> | 2021-09-30 14:31:10 +0000 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2021-10-01 13:31:00 +0100 |
| commit | efc2d0f20a9dab2d0e92a271dc4b8e3496377739 (patch) | |
| tree | fa0b24a0c10e8f42a9da2e267bc0ba93856546dc /arch/arm64/kernel/relocate_kernel.S | |
| parent | 3744b5280e67f54579abe92576deec0079242323 (diff) | |
arm64: kexec: keep MMU enabled during kexec relocation
Now, that we have linear map page tables configured, keep MMU enabled
to allow faster relocation of segments to final destination.
Cavium ThunderX2:
Kernel Image size: 38M Iniramfs size: 46M Total relocation size: 84M
MMU-disabled:
relocation 7.489539915s
MMU-enabled:
relocation 0.03946095s
Broadcom Stingray:
The performance data: for a moderate size kernel + initramfs: 25M the
relocation was taking 0.382s, with enabled MMU it now takes
0.019s only or x20 improvement.
The time is proportional to the size of relocation, therefore if initramfs
is larger, 100M it could take over a second.
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Tested-by: Pingfan Liu <piliu@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210930143113.1502553-13-pasha.tatashin@soleen.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/relocate_kernel.S')
| -rw-r--r-- | arch/arm64/kernel/relocate_kernel.S | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S index 2b80232246f7..f0a3df9e18a3 100644 --- a/arch/arm64/kernel/relocate_kernel.S +++ b/arch/arm64/kernel/relocate_kernel.S @@ -4,6 +4,8 @@ * * Copyright (C) Linaro. * Copyright (C) Huawei Futurewei Technologies. + * Copyright (C) 2021, Microsoft Corporation. + * Pasha Tatashin <pasha.tatashin@soleen.com> */ #include <linux/kexec.h> @@ -15,6 +17,13 @@ #include <asm/sysreg.h> #include <asm/virt.h> +.macro turn_off_mmu tmp1, tmp2 + mov_q \tmp1, INIT_SCTLR_EL1_MMU_OFF + pre_disable_mmu_workaround + msr sctlr_el1, \tmp1 + isb +.endm + .section ".kexec_relocate.text", "ax" /* * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it. @@ -32,22 +41,21 @@ SYM_CODE_START(arm64_relocate_new_kernel) ldr x18, [x0, #KIMAGE_ARCH_ZERO_PAGE] /* x18 = zero page for BBM */ ldr x17, [x0, #KIMAGE_ARCH_TTBR1] /* x17 = linear map copy */ ldr x16, [x0, #KIMAGE_HEAD] /* x16 = kimage_head */ - mov x14, xzr /* x14 = entry ptr */ - mov x13, xzr /* x13 = copy dest */ + ldr x22, [x0, #KIMAGE_ARCH_PHYS_OFFSET] /* x22 phys_offset */ raw_dcache_line_size x15, x1 /* x15 = dcache line size */ break_before_make_ttbr_switch x18, x17, x1, x2 /* set linear map */ .Lloop: and x12, x16, PAGE_MASK /* x12 = addr */ - + sub x12, x12, x22 /* Convert x12 to virt */ /* Test the entry flags. */ .Ltest_source: tbz x16, IND_SOURCE_BIT, .Ltest_indirection /* Invalidate dest page to PoC. */ - mov x2, x13 - add x1, x2, #PAGE_SIZE - dcache_by_myline_op ivac, sy, x2, x1, x15, x20 + mov x19, x13 copy_page x13, x12, x1, x2, x3, x4, x5, x6, x7, x8 + add x1, x19, #PAGE_SIZE + dcache_by_myline_op civac, sy, x19, x1, x15, x20 b .Lnext .Ltest_indirection: tbz x16, IND_INDIRECTION_BIT, .Ltest_destination @@ -64,19 +72,20 @@ SYM_CODE_START(arm64_relocate_new_kernel) ic iallu dsb nsh isb + ldr x4, [x0, #KIMAGE_START] /* relocation start */ + ldr x1, [x0, #KIMAGE_ARCH_EL2_VECTORS] /* relocation start */ + ldr x0, [x0, #KIMAGE_ARCH_DTB_MEM] /* dtb address */ + turn_off_mmu x12, x13 /* Start new image. */ - ldr x1, [x0, #KIMAGE_ARCH_EL2_VECTORS] /* relocation start */ cbz x1, .Lel1 - ldr x1, [x0, #KIMAGE_START] /* relocation start */ - ldr x2, [x0, #KIMAGE_ARCH_DTB_MEM] /* dtb address */ + mov x1, x4 /* relocation start */ + mov x2, x0 /* dtb address */ mov x3, xzr mov x4, xzr mov x0, #HVC_SOFT_RESTART hvc #0 /* Jumps from el2 */ .Lel1: - ldr x4, [x0, #KIMAGE_START] /* relocation start */ - ldr x0, [x0, #KIMAGE_ARCH_DTB_MEM] /* dtb address */ mov x2, xzr mov x3, xzr br x4 /* Jumps from el1 */ |