[PATCH v5 14/17] arm64: kexec: move relocation function setup and clean up

From: Pavel Tatashin
Date: Mon Sep 23 2019 - 16:35:32 EST


Currently, kernel relocation function is configured in machine_kexec()
at the time of kexec reboot by using control_code_page.

This operation, however, is more logical to be done during kexec_load,
and thus remove from reboot time. Move, setup of this function to
newly added machine_kexec_post_load().

In addition, do some cleanup: add infor about reloction function to
kexec_image_info(), and remove extra messages from machine_kexec().

Make dtb_mem, always available, if CONFIG_KEXEC_FILE is not configured
dtb_mem is set to zero anyway.

Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
---
arch/arm64/include/asm/kexec.h | 3 +-
arch/arm64/kernel/machine_kexec.c | 49 +++++++++++--------------------
2 files changed, 19 insertions(+), 33 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 12a561a54128..d15ca1ca1e83 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -90,14 +90,15 @@ static inline void crash_prepare_suspend(void) {}
static inline void crash_post_resume(void) {}
#endif

-#ifdef CONFIG_KEXEC_FILE
#define ARCH_HAS_KIMAGE_ARCH

struct kimage_arch {
void *dtb;
unsigned long dtb_mem;
+ unsigned long kern_reloc;
};

+#ifdef CONFIG_KEXEC_FILE
extern const struct kexec_file_ops kexec_image_ops;

struct kimage;
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 0df8493624e0..9b41da50e6f7 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -42,6 +42,7 @@ static void _kexec_image_info(const char *func, int line,
pr_debug(" start: %lx\n", kimage->start);
pr_debug(" head: %lx\n", kimage->head);
pr_debug(" nr_segments: %lu\n", kimage->nr_segments);
+ pr_debug(" kern_reloc: %pa\n", &kimage->arch.kern_reloc);

for (i = 0; i < kimage->nr_segments; i++) {
pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
@@ -58,6 +59,19 @@ void machine_kexec_cleanup(struct kimage *kimage)
/* Empty routine needed to avoid build errors. */
}

+int machine_kexec_post_load(struct kimage *kimage)
+{
+ unsigned long kern_reloc;
+
+ kern_reloc = page_to_phys(kimage->control_code_page);
+ memcpy(__va(kern_reloc), arm64_relocate_new_kernel,
+ arm64_relocate_new_kernel_size);
+ kimage->arch.kern_reloc = kern_reloc;
+
+ kexec_image_info(kimage);
+ return 0;
+}
+
/**
* machine_kexec_prepare - Prepare for a kexec reboot.
*
@@ -67,8 +81,6 @@ void machine_kexec_cleanup(struct kimage *kimage)
*/
int machine_kexec_prepare(struct kimage *kimage)
{
- kexec_image_info(kimage);
-
if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) {
pr_err("Can't kexec: CPUs are stuck in the kernel.\n");
return -EBUSY;
@@ -143,8 +155,7 @@ static void kexec_segment_flush(const struct kimage *kimage)
*/
void machine_kexec(struct kimage *kimage)
{
- phys_addr_t reboot_code_buffer_phys;
- void *reboot_code_buffer;
+ void *reboot_code_buffer = phys_to_virt(kimage->arch.kern_reloc);
bool in_kexec_crash = (kimage == kexec_crash_image);
bool stuck_cpus = cpus_are_stuck_in_kernel();

@@ -155,30 +166,8 @@ void machine_kexec(struct kimage *kimage)
WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()),
"Some CPUs may be stale, kdump will be unreliable.\n");

- reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
- reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
-
kexec_image_info(kimage);

- pr_debug("%s:%d: control_code_page: %p\n", __func__, __LINE__,
- kimage->control_code_page);
- pr_debug("%s:%d: reboot_code_buffer_phys: %pa\n", __func__, __LINE__,
- &reboot_code_buffer_phys);
- pr_debug("%s:%d: reboot_code_buffer: %p\n", __func__, __LINE__,
- reboot_code_buffer);
- pr_debug("%s:%d: relocate_new_kernel: %p\n", __func__, __LINE__,
- arm64_relocate_new_kernel);
- pr_debug("%s:%d: relocate_new_kernel_size: 0x%lx(%lu) bytes\n",
- __func__, __LINE__, arm64_relocate_new_kernel_size,
- arm64_relocate_new_kernel_size);
-
- /*
- * Copy arm64_relocate_new_kernel to the reboot_code_buffer for use
- * after the kernel is shut down.
- */
- memcpy(reboot_code_buffer, arm64_relocate_new_kernel,
- arm64_relocate_new_kernel_size);
-
/* Flush the reboot_code_buffer in preparation for its execution. */
__flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size);

@@ -214,12 +203,8 @@ void machine_kexec(struct kimage *kimage)
* userspace (kexec-tools).
* In kexec_file case, the kernel starts directly without purgatory.
*/
- cpu_soft_restart(reboot_code_buffer_phys, kimage->head, kimage->start,
-#ifdef CONFIG_KEXEC_FILE
- kimage->arch.dtb_mem);
-#else
- 0);
-#endif
+ cpu_soft_restart(kimage->arch.kern_reloc, kimage->head, kimage->start,
+ kimage->arch.dtb_mem);

BUG(); /* Should never get here. */
}
--
2.23.0