arm64: kexec: use ld script for relocation function

Currently, relocation code declares start and end variables
which are used to compute its size.

The better way to do this is to use ld script, and put relocation
function in its own section.

Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210930143113.1502553-11-pasha.tatashin@soleen.com
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/include/asm/sections.h b/arch/arm64/include/asm/sections.h
index e4ad9db..152cb35 100644 (file)
--- a/arch/arm64/include/asm/sections.h
+++ b/arch/arm64/include/asm/sections.h
@@ -21,5 +21,6 @@ extern char __exittext_begin[], __exittext_end[];
 extern char __irqentry_text_start[], __irqentry_text_end[];
 extern char __mmuoff_data_start[], __mmuoff_data_end[];
 extern char __entry_tramp_text_start[], __entry_tramp_text_end[];
+extern char __relocate_new_kernel_start[], __relocate_new_kernel_end[];
 
 #endif /* __ASM_SECTIONS_H */

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index cf5d6f2..320442d 100644 (file)
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -21,14 +21,11 @@
 #include <asm/mmu.h>
 #include <asm/mmu_context.h>
 #include <asm/page.h>
+#include <asm/sections.h>
 #include <asm/trans_pgd.h>
 
 #include "cpu-reset.h"
 
-/* Global variables for the arm64_relocate_new_kernel routine. */
-extern const unsigned char arm64_relocate_new_kernel[];
-extern const unsigned long arm64_relocate_new_kernel_size;
-
 /**
  * kexec_image_info - For debugging output.
  */
@@ -163,6 +160,7 @@ static void *kexec_page_alloc(void *arg)
 int machine_kexec_post_load(struct kimage *kimage)
 {
        void *reloc_code = page_to_virt(kimage->control_code_page);
+       long reloc_size;
        struct trans_pgd_info info = {
                .trans_alloc_page       = kexec_page_alloc,
                .trans_alloc_arg        = kimage,
@@ -183,17 +181,15 @@ int machine_kexec_post_load(struct kimage *kimage)
                        return rc;
        }
 
-       memcpy(reloc_code, arm64_relocate_new_kernel,
-              arm64_relocate_new_kernel_size);
+       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);
 
        /* Flush the reloc_code in preparation for its execution. */
        dcache_clean_inval_poc((unsigned long)reloc_code,
-                              (unsigned long)reloc_code +
-                              arm64_relocate_new_kernel_size);
+                              (unsigned long)reloc_code + reloc_size);
        icache_inval_pou((uintptr_t)reloc_code,
-                        (uintptr_t)reloc_code +
-                        arm64_relocate_new_kernel_size);
+                        (uintptr_t)reloc_code + reloc_size);
        kexec_list_flush(kimage);
        kexec_image_info(kimage);
 

diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index b4fb973..2227741 100644 (file)
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -15,6 +15,7 @@
 #include <asm/sysreg.h>
 #include <asm/virt.h>
 
+.section    ".kexec_relocate.text", "ax"
 /*
  * arm64_relocate_new_kernel - Put a 2nd stage image in place and boot it.
  *
@@ -77,16 +78,3 @@ SYM_CODE_START(arm64_relocate_new_kernel)
        mov     x3, xzr
        br      x4                              /* Jumps from el1 */
 SYM_CODE_END(arm64_relocate_new_kernel)
-
-.align 3       /* To keep the 64-bit values below naturally aligned. */
-
-.Lcopy_end:
-.org   KEXEC_CONTROL_PAGE_SIZE
-
-/*
- * arm64_relocate_new_kernel_size - Number of bytes to copy to the
- * control_code_page.
- */
-.globl arm64_relocate_new_kernel_size
-arm64_relocate_new_kernel_size:
-       .quad   .Lcopy_end - arm64_relocate_new_kernel

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index f6b1a88..0760331 100644 (file)
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -63,6 +63,7 @@
 #include <asm-generic/vmlinux.lds.h>
 #include <asm/cache.h>
 #include <asm/kernel-pgtable.h>
+#include <asm/kexec.h>
 #include <asm/memory.h>
 #include <asm/page.h>
 
@@ -100,6 +101,16 @@ jiffies = jiffies_64;
 #define HIBERNATE_TEXT
 #endif
 
+#ifdef CONFIG_KEXEC_CORE
+#define KEXEC_TEXT                                     \
+       . = ALIGN(SZ_4K);                               \
+       __relocate_new_kernel_start = .;                \
+       *(.kexec_relocate.text)                         \
+       __relocate_new_kernel_end = .;
+#else
+#define KEXEC_TEXT
+#endif
+
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
 #define TRAMP_TEXT                                     \
        . = ALIGN(PAGE_SIZE);                           \
@@ -160,6 +171,7 @@ SECTIONS
                        HYPERVISOR_TEXT
                        IDMAP_TEXT
                        HIBERNATE_TEXT
+                       KEXEC_TEXT
                        TRAMP_TEXT
                        *(.fixup)
                        *(.gnu.warning)
@@ -348,3 +360,10 @@ ASSERT(swapper_pg_dir - reserved_pg_dir == RESERVED_SWAPPER_OFFSET,
 ASSERT(swapper_pg_dir - tramp_pg_dir == TRAMP_SWAPPER_OFFSET,
        "TRAMP_SWAPPER_OFFSET is wrong!")
 #endif
+
+#ifdef CONFIG_KEXEC_CORE
+/* kexec relocation code should fit into one KEXEC_CONTROL_PAGE_SIZE */
+ASSERT(__relocate_new_kernel_end - (__relocate_new_kernel_start & ~(SZ_4K - 1))
+       <= SZ_4K, "kexec relocation code is too big or misaligned")
+ASSERT(KEXEC_CONTROL_PAGE_SIZE >= SZ_4K, "KEXEC_CONTROL_PAGE_SIZE is broken")
+#endif