Messages in this thread | | | Date | Wed, 29 Apr 2020 18:35:06 +0100 | From | Marc Zyngier <> | Subject | Re: [PATCH v9 15/18] arm64: kexec: kexec EL2 vectors |
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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@soleen.com> > --- > 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...
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