Re: [PATCH v9 15/18] arm64: kexec: kexec EL2 vectors
From: Marc Zyngier
Date: Wed Apr 29 2020 - 13:35:11 EST
On 2020-03-26 03:24, Pavel Tatashin wrote:
If we have a EL2 mode without VHE, the EL2 vectors are needed in order
to switch to EL2 and jump to new world with hyperivsor privileges.
Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
---
arch/arm64/include/asm/kexec.h | 5 +++++
arch/arm64/kernel/asm-offsets.c | 1 +
arch/arm64/kernel/machine_kexec.c | 5 +++++
arch/arm64/kernel/relocate_kernel.S | 35 +++++++++++++++++++++++++++++
4 files changed, 46 insertions(+)
diff --git a/arch/arm64/include/asm/kexec.h
b/arch/arm64/include/asm/kexec.h
index d944c2e289b2..0f758fd51518 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -95,6 +95,7 @@ static inline void crash_post_resume(void) {}
extern const unsigned long kexec_relocate_code_size;
extern const unsigned char kexec_relocate_code_start[];
extern const unsigned long kexec_kern_reloc_offset;
+extern const unsigned long kexec_el2_vectors_offset;
#endif
/*
@@ -104,6 +105,9 @@ extern const unsigned long kexec_kern_reloc_offset;
* kernel, or purgatory entry address).
* kern_arg0 first argument to kernel is its dtb address. The other
* arguments are currently unused, and must be set to 0
+ * 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.
*/
struct kern_reloc_arg {
phys_addr_t head;
@@ -112,6 +116,7 @@ struct kern_reloc_arg {
phys_addr_t kern_arg1;
phys_addr_t kern_arg2;
phys_addr_t kern_arg3;
+ phys_addr_t el2_vector;
};
#define ARCH_HAS_KIMAGE_ARCH
diff --git a/arch/arm64/kernel/asm-offsets.c
b/arch/arm64/kernel/asm-offsets.c
index 448230684749..ff974b648347 100644
--- a/arch/arm64/kernel/asm-offsets.c
+++ b/arch/arm64/kernel/asm-offsets.c
@@ -136,6 +136,7 @@ int main(void)
DEFINE(KEXEC_KRELOC_KERN_ARG1, offsetof(struct kern_reloc_arg,
kern_arg1));
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));
#endif
return 0;
}
diff --git a/arch/arm64/kernel/machine_kexec.c
b/arch/arm64/kernel/machine_kexec.c
index ab571fca9bd1..bd398def7627 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -84,6 +84,11 @@ int machine_kexec_post_load(struct kimage *kimage)
kern_reloc_arg->head = kimage->head;
kern_reloc_arg->entry_addr = kimage->start;
kern_reloc_arg->kern_arg0 = kimage->arch.dtb_mem;
+ /* Setup vector table only when EL2 is available, but no VHE */
+ if (is_hyp_mode_available() && !is_kernel_in_hyp_mode()) {
+ kern_reloc_arg->el2_vector = __pa(reloc_code)
+ + kexec_el2_vectors_offset;
+ }
kexec_image_info(kimage);
return 0;
diff --git a/arch/arm64/kernel/relocate_kernel.S
b/arch/arm64/kernel/relocate_kernel.S
index aa9f2b2cd77c..6fd2fc0ef373 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -89,6 +89,38 @@ ENTRY(arm64_relocate_new_kernel)
.ltorg
END(arm64_relocate_new_kernel)
+.macro el1_sync_64
+ br x4 /* Jump to new world from el2 */
+ .fill 31, 4, 0 /* Set other 31 instr to zeroes */
+.endm
The common idiom to write this is to align the beginning of the
macro, and not to bother about what follows:
.macro whatever
.align 7
br x4
.endm
Specially given that 0 is an undefined instruction, and I really hate to
see
those in the actual text. On the contrary, .align generates NOPs.
+
+.macro invalid_vector label
+\label:
+ b \label
+ .fill 31, 4, 0 /* Set other 31 instr to zeroes */
+.endm
+
+/* el2 vectors - switch el2 here while we restore the memory image. */
+ .align 11
+ENTRY(kexec_el2_vectors)
Please see commit 617a2f392c92 ("arm64: kvm: Annotate assembly using
modern
annoations"), and follow the same pattern.
+ invalid_vector el2_sync_invalid_sp0 /* Synchronous EL2t */
+ invalid_vector el2_irq_invalid_sp0 /* IRQ EL2t */
+ invalid_vector el2_fiq_invalid_sp0 /* FIQ EL2t */
+ invalid_vector el2_error_invalid_sp0 /* Error EL2t */
+ invalid_vector el2_sync_invalid_spx /* Synchronous EL2h */
+ invalid_vector el2_irq_invalid_spx /* IRQ EL2h */
+ invalid_vector el2_fiq_invalid_spx /* FIQ EL2h */
+ invalid_vector el2_error_invalid_spx /* Error EL2h */
+ el1_sync_64 /* Synchronous 64-bit EL1 */
+ invalid_vector el1_irq_invalid_64 /* IRQ 64-bit EL1 */
+ invalid_vector el1_fiq_invalid_64 /* FIQ 64-bit EL1 */
+ invalid_vector el1_error_invalid_64 /* Error 64-bit EL1 */
+ invalid_vector el1_sync_invalid_32 /* Synchronous 32-bit EL1 */
+ invalid_vector el1_irq_invalid_32 /* IRQ 32-bit EL1 */
+ invalid_vector el1_fiq_invalid_32 /* FIQ 32-bit EL1 */
+ invalid_vector el1_error_invalid_32 /* Error 32-bit EL1 */
+END(kexec_el2_vectors)
Please write the vectors in 4 groups of 4, as this makes it a lot easier
to follow what is what.
+
.Lkexec_relocate_code_end:
.org KEXEC_CONTROL_PAGE_SIZE
.align 3 /* To keep the 64-bit values below naturally aligned. */
@@ -102,3 +134,6 @@ kexec_relocate_code_size:
.globl kexec_kern_reloc_offset
kexec_kern_reloc_offset:
.quad arm64_relocate_new_kernel - kexec_relocate_code_start
+.globl kexec_el2_vectors_offset
+kexec_el2_vectors_offset:
+ .quad kexec_el2_vectors - kexec_relocate_code_start
Thanks,
M.
--
Jazz is not dead. It just smells funny...