Configure a page table located in kexec-safe memory that has the following mappings:
1. identity mapping for text of relocation function with executable permission. 2. va mappings for all source ranges 3. va mappings for all destination ranges. Signed-off-by: Pavel Tatashin <[email protected]> --- arch/arm64/include/asm/kexec.h | 12 ++++ arch/arm64/kernel/asm-offsets.c | 6 ++ arch/arm64/kernel/machine_kexec.c | 91 ++++++++++++++++++++++++++++++- 3 files changed, 108 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h index b96d8a6aac80..049cde429b1b 100644 --- a/arch/arm64/include/asm/kexec.h +++ b/arch/arm64/include/asm/kexec.h @@ -105,6 +105,12 @@ extern const char arm64_kexec_el2_vectors[]; * el2_vector If present means that relocation routine will go to EL1 * from EL2 to do the copy, and then back to EL2 to do the jump * to new world. + * trans_ttbr0 idmap for relocation function and its argument + * trans_ttbr1 map for source/destination addresses. + * trans_t0sz t0sz for idmap page in trans_ttbr0 + * src_addr start address for source pages. + * dst_addr start address for destination pages. + * copy_len Number of bytes that need to be copied */ struct kern_reloc_arg { phys_addr_t head; @@ -114,6 +120,12 @@ struct kern_reloc_arg { phys_addr_t kern_arg2; phys_addr_t kern_arg3; phys_addr_t el2_vector; + phys_addr_t trans_ttbr0; + phys_addr_t trans_ttbr1; + unsigned long trans_t0sz; + unsigned long src_addr; + unsigned long dst_addr; + unsigned long copy_len; }; #define ARCH_HAS_KIMAGE_ARCH diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 8a9475be1b62..06278611451d 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -160,6 +160,12 @@ int main(void) DEFINE(KEXEC_KRELOC_KERN_ARG2, offsetof(struct kern_reloc_arg, kern_arg2)); DEFINE(KEXEC_KRELOC_KERN_ARG3, offsetof(struct kern_reloc_arg, kern_arg3)); DEFINE(KEXEC_KRELOC_EL2_VECTOR, offsetof(struct kern_reloc_arg, el2_vector)); + DEFINE(KEXEC_KRELOC_TRANS_TTBR0, offsetof(struct kern_reloc_arg, trans_ttbr0)); + DEFINE(KEXEC_KRELOC_TRANS_TTBR1, offsetof(struct kern_reloc_arg, trans_ttbr1)); + DEFINE(KEXEC_KRELOC_TRANS_T0SZ, offsetof(struct kern_reloc_arg, trans_t0sz)); + DEFINE(KEXEC_KRELOC_SRC_ADDR, offsetof(struct kern_reloc_arg, src_addr)); + DEFINE(KEXEC_KRELOC_DST_ADDR, offsetof(struct kern_reloc_arg, dst_addr)); + DEFINE(KEXEC_KRELOC_COPY_LEN, offsetof(struct kern_reloc_arg, copy_len)); #endif return 0; } diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c index 41d1e3ca13f8..dc1b7e5a54fb 100644 --- a/arch/arm64/kernel/machine_kexec.c +++ b/arch/arm64/kernel/machine_kexec.c @@ -21,6 +21,7 @@ #include <asm/mmu_context.h> #include <asm/page.h> #include <asm/sections.h> +#include <asm/trans_pgd.h> #include "cpu-reset.h" @@ -71,11 +72,91 @@ static void *kexec_page_alloc(void *arg) return page_address(page); } +/* + * Map source segments starting from src_va, and map destination + * segments starting from dst_va, and return size of copy in + * *copy_len argument. + * Relocation function essentially needs to do: + * memcpy(dst_va, src_va, copy_len); + */ +static int map_segments(struct kimage *kimage, pgd_t *pgdp, + struct trans_pgd_info *info, + unsigned long src_va, + unsigned long dst_va, + unsigned long *copy_len) +{ + unsigned long *ptr = 0; + unsigned long dest = 0; + unsigned long len = 0; + unsigned long entry, addr; + int rc; + + for (entry = kimage->head; !(entry & IND_DONE); entry = *ptr++) { + addr = entry & PAGE_MASK; + + switch (entry & IND_FLAGS) { + case IND_DESTINATION: + dest = addr; + break; + case IND_INDIRECTION: + ptr = __va(addr); + if (rc) + return rc; + break; + case IND_SOURCE: + rc = trans_pgd_map_page(info, pgdp, __va(addr), + src_va, PAGE_KERNEL); + if (rc) + return rc; + rc = trans_pgd_map_page(info, pgdp, __va(dest), + dst_va, PAGE_KERNEL); + if (rc) + return rc; + dest += PAGE_SIZE; + src_va += PAGE_SIZE; + dst_va += PAGE_SIZE; + len += PAGE_SIZE; + } + } + *copy_len = len; + + return 0; +} + +static int mmu_relocate_setup(struct kimage *kimage, void *reloc_code, + struct kern_reloc_arg *kern_reloc_arg) +{ + struct trans_pgd_info info = { + .trans_alloc_page = kexec_page_alloc, + .trans_alloc_arg = kimage, + }; + pgd_t *trans_pgd = kexec_page_alloc(kimage); + int rc; + + if (!trans_pgd) + return -ENOMEM; + + /* idmap relocation function */ + rc = trans_pgd_idmap_page(&info, &kern_reloc_arg->trans_ttbr0, + &kern_reloc_arg->trans_t0sz, reloc_code); + if (rc) + return rc; + + kern_reloc_arg->src_addr = _PAGE_OFFSET(VA_BITS_MIN); + kern_reloc_arg->dst_addr = _PAGE_OFFSET(VA_BITS_MIN - 1); + kern_reloc_arg->trans_ttbr1 = phys_to_ttbr(__pa(trans_pgd)); + + rc = map_segments(kimage, trans_pgd, &info, kern_reloc_arg->src_addr, + kern_reloc_arg->dst_addr, &kern_reloc_arg->copy_len); + return rc; +} + int machine_kexec_post_load(struct kimage *kimage) { void *reloc_code = page_to_virt(kimage->control_code_page); struct kern_reloc_arg *kern_reloc_arg = kexec_page_alloc(kimage); long func_offset, vector_offset, reloc_size; + int rc = 0; if (!kern_reloc_arg) return -ENOMEM; @@ -95,6 +176,14 @@ int machine_kexec_post_load(struct kimage *kimage) if (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) kern_reloc_arg->el2_vector = __pa(reloc_code) + vector_offset; + /* + * If relocation is not needed, we do not need to enable MMU in + * relocation routine, therefore do not create page tables for + * scenarios such as crash kernel + */ + if (!(kimage->head & IND_DONE)) + rc = mmu_relocate_setup(kimage, reloc_code, kern_reloc_arg); + kexec_image_info(kimage); /* Flush the reloc_code in preparation for its execution. */ @@ -103,7 +192,7 @@ int machine_kexec_post_load(struct kimage *kimage) reloc_size); __flush_dcache_area(kern_reloc_arg, sizeof(struct kern_reloc_arg)); - return 0; + return rc; } /** -- 2.25.1
