Commit 878fdbd7 authored by Pasha Tatashin's avatar Pasha Tatashin Committed by Will Deacon
Browse files

arm64: kexec: pass kimage as the only argument to relocation function 



Currently, kexec relocation function (arm64_relocate_new_kernel) accepts
the following arguments:

head:		start of array that contains relocation information.
entry:		entry point for new kernel or purgatory.
dtb_mem:	first and only argument to entry.

The number of arguments cannot be easily expended, because this
function is also called from HVC_SOFT_RESTART, which preserves only
three arguments. And, also arm64_relocate_new_kernel is written in
assembly but called without stack, thus no place to move extra arguments
to free registers.

Soon, we will need to pass more arguments: once we enable MMU we
will need to pass information about page tables.

Pass kimage to arm64_relocate_new_kernel, and teach it to get the
required fields from kimage.

Signed-off-by: default avatarPasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210930143113.1502553-8-pasha.tatashin@soleen.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 3036ec59

arch/arm64/kernel/asm-offsets.c

+7 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 


#include <linux/arm_sdei.h>

#include <linux/sched.h>

#include <linux/kexec.h>

#include <linux/mm.h>

#include <linux/dma-mapping.h>

#include <linux/kvm_host.h>
@@ -170,6 +171,12 @@ int main(void) 
  DEFINE(PTRAUTH_KERNEL_KEY_APIA,	offsetof(struct ptrauth_keys_kernel, apia));

#endif

  BLANK();

#endif

#ifdef CONFIG_KEXEC_CORE

  DEFINE(KIMAGE_ARCH_DTB_MEM,		offsetof(struct kimage, arch.dtb_mem));

  DEFINE(KIMAGE_HEAD,			offsetof(struct kimage, head));

  DEFINE(KIMAGE_START,			offsetof(struct kimage, start));

  BLANK();

#endif

  return 0;

}

arch/arm64/kernel/machine_kexec.c

+5 −2
Original line number Diff line number Diff line
@@ -84,6 +84,9 @@ static void kexec_list_flush(struct kimage *kimage) 
{

	kimage_entry_t *entry;



	dcache_clean_inval_poc((unsigned long)kimage,

			       (unsigned long)kimage + sizeof(*kimage));



	for (entry = &kimage->head; ; entry++) {

		unsigned int flag;

		unsigned long addr;
@@ -206,8 +209,8 @@ void machine_kexec(struct kimage *kimage) 
		restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem,

			0, 0);

	} else {

		cpu_soft_restart(kimage->arch.kern_reloc, kimage->head,

				 kimage->start, kimage->arch.dtb_mem);

		cpu_soft_restart(kimage->arch.kern_reloc, virt_to_phys(kimage),

				 0, 0);

	}



	BUG(); /* Should never get here. */

arch/arm64/kernel/relocate_kernel.S

+4 −6
Original line number Diff line number Diff line
@@ -27,9 +27,7 @@ 
 */

SYM_CODE_START(arm64_relocate_new_kernel)

	/* Setup the list loop variables. */

	mov	x18, x2				/* x18 = dtb address */

	mov	x17, x1				/* x17 = kimage_start */

	mov	x16, x0				/* x16 = kimage_head */

	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 */
@@ -63,12 +61,12 @@ SYM_CODE_START(arm64_relocate_new_kernel) 
	isb



	/* Start new image. */

	mov	x0, x18

	ldr	x4, [x0, #KIMAGE_START]		/* relocation start */

	ldr	x0, [x0, #KIMAGE_ARCH_DTB_MEM]	/* dtb address */

	mov	x1, xzr

	mov	x2, xzr

	mov	x3, xzr

	br	x17



	br	x4

SYM_CODE_END(arm64_relocate_new_kernel)



.align 3	/* To keep the 64-bit values below naturally aligned. */