[PATCH v13 14/18] arm64: kexec: install a copy of the linear-map
Pavel Tatashin
pasha.tatashin at soleen.com
Thu Apr 8 05:05:33 BST 2021
To perform the kexec relocations with the MMU enabled, we need a copy
of the linear map.
Create one, and install it from the relocation code. This has to be done
from the assembly code as it will be idmapped with TTBR0. The kernel
runs in TTRB1, so can't use the break-before-make sequence on the mapping
it is executing from.
The makes no difference yet as the relocation code runs with the MMU
disabled.
Co-developed-by: James Morse <james.morse at arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin at soleen.com>
---
arch/arm64/include/asm/assembler.h | 19 +++++++++++++++++++
arch/arm64/include/asm/kexec.h | 2 ++
arch/arm64/kernel/asm-offsets.c | 2 ++
arch/arm64/kernel/hibernate-asm.S | 20 --------------------
arch/arm64/kernel/machine_kexec.c | 16 ++++++++++++++--
arch/arm64/kernel/relocate_kernel.S | 3 +++
6 files changed, 40 insertions(+), 22 deletions(-)
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 29061b76aab6..3ce8131ad660 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -425,6 +425,25 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU
isb
.endm
+/*
+ * To prevent the possibility of old and new partial table walks being visible
+ * in the tlb, switch the ttbr to a zero page when we invalidate the old
+ * records. D4.7.1 'General TLB maintenance requirements' in ARM DDI 0487A.i
+ * Even switching to our copied tables will cause a changed output address at
+ * each stage of the walk.
+ */
+ .macro break_before_make_ttbr_switch zero_page, page_table, tmp, tmp2
+ phys_to_ttbr \tmp, \zero_page
+ msr ttbr1_el1, \tmp
+ isb
+ tlbi vmalle1
+ dsb nsh
+ phys_to_ttbr \tmp, \page_table
+ offset_ttbr1 \tmp, \tmp2
+ msr ttbr1_el1, \tmp
+ isb
+ .endm
+
/*
* reset_pmuserenr_el0 - reset PMUSERENR_EL0 if PMUv3 present
*/
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 305cf0840ed3..59ac166daf53 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -97,6 +97,8 @@ struct kimage_arch {
phys_addr_t dtb_mem;
phys_addr_t kern_reloc;
phys_addr_t el2_vectors;
+ phys_addr_t ttbr1;
+ phys_addr_t zero_page;
/* Core ELF header buffer */
void *elf_headers;
unsigned long elf_headers_mem;
diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c
index 2e3278df1fc3..609362b5aa76 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -158,6 +158,8 @@ int main(void)
#ifdef CONFIG_KEXEC_CORE
DEFINE(KIMAGE_ARCH_DTB_MEM, offsetof(struct kimage, arch.dtb_mem));
DEFINE(KIMAGE_ARCH_EL2_VECTORS, offsetof(struct kimage, arch.el2_vectors));
+ DEFINE(KIMAGE_ARCH_ZERO_PAGE, offsetof(struct kimage, arch.zero_page));
+ DEFINE(KIMAGE_ARCH_TTBR1, offsetof(struct kimage, arch.ttbr1));
DEFINE(KIMAGE_HEAD, offsetof(struct kimage, head));
DEFINE(KIMAGE_START, offsetof(struct kimage, start));
BLANK();
diff --git a/arch/arm64/kernel/hibernate-asm.S b/arch/arm64/kernel/hibernate-asm.S
index 8ccca660034e..a31e621ba867 100644
--- a/arch/arm64/kernel/hibernate-asm.S
+++ b/arch/arm64/kernel/hibernate-asm.S
@@ -15,26 +15,6 @@
#include <asm/page.h>
#include <asm/virt.h>
-/*
- * To prevent the possibility of old and new partial table walks being visible
- * in the tlb, switch the ttbr to a zero page when we invalidate the old
- * records. D4.7.1 'General TLB maintenance requirements' in ARM DDI 0487A.i
- * Even switching to our copied tables will cause a changed output address at
- * each stage of the walk.
- */
-.macro break_before_make_ttbr_switch zero_page, page_table, tmp, tmp2
- phys_to_ttbr \tmp, \zero_page
- msr ttbr1_el1, \tmp
- isb
- tlbi vmalle1
- dsb nsh
- phys_to_ttbr \tmp, \page_table
- offset_ttbr1 \tmp, \tmp2
- msr ttbr1_el1, \tmp
- isb
-.endm
-
-
/*
* Resume from hibernate
*
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index f1451d807708..c875ef522e53 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -153,6 +153,8 @@ static void *kexec_page_alloc(void *arg)
int machine_kexec_post_load(struct kimage *kimage)
{
+ int rc;
+ pgd_t *trans_pgd;
void *reloc_code = page_to_virt(kimage->control_code_page);
long reloc_size;
struct trans_pgd_info info = {
@@ -169,12 +171,22 @@ int machine_kexec_post_load(struct kimage *kimage)
kimage->arch.el2_vectors = 0;
if (is_hyp_callable()) {
- int rc = trans_pgd_copy_el2_vectors(&info,
- &kimage->arch.el2_vectors);
+ rc = trans_pgd_copy_el2_vectors(&info,
+ &kimage->arch.el2_vectors);
if (rc)
return rc;
}
+ /* Create a copy of the linear map */
+ trans_pgd = kexec_page_alloc(kimage);
+ if (!trans_pgd)
+ return -ENOMEM;
+ rc = trans_pgd_create_copy(&info, &trans_pgd, PAGE_OFFSET, PAGE_END);
+ if (rc)
+ return rc;
+ kimage->arch.ttbr1 = __pa(trans_pgd);
+ kimage->arch.zero_page = __pa(empty_zero_page);
+
reloc_size = __relocate_new_kernel_end - __relocate_new_kernel_start;
memcpy(reloc_code, __relocate_new_kernel_start, reloc_size);
kimage->arch.kern_reloc = __pa(reloc_code);
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index 7a600ba33ae1..e83b6380907d 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -29,10 +29,13 @@
*/
SYM_CODE_START(arm64_relocate_new_kernel)
/* Setup the list loop variables. */
+ 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 */
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 */
--
2.25.1
More information about the kexec
mailing list