[PATCH v2] arm64: Add support for additional relocations in the kexec purgatory code

[Pratyush Anand]

On Thursday 20 October 2016 04:13 PM, Catalin Marinas wrote:
> When compiling the kexec-tools with gcc6, the following additional
> reolcations are generated in the purgatory.ro file:
>
> R_AARCH64_ADR_PREL_PG_HI21
> R_AARCH64_ADD_ABS_LO12_NC
> R_AARCH64_LDST64_ABS_LO12_NC
>
> This patch modifies the arm64 machine_apply_elf_rel() function to handle
> these relocations.

Noticed that, gcc version of fedora koji(6.2.1-2.fc25) inserts another 
relocation and kexec-tools generates following error.

machine_apply_elf_rel: ERROR Unknown type: 261

I have a fixup here:
https://github.com/pratyushanand/kexec-tools/commit/0eb8a908f617e0f957df7fb3ef293596f47e6832

May be I will send them separately.

~Pratyush
>
> Cc: Geoff Levand <geoff at infradead.org>
> Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
> ---
>
> Changes for v2:
> - Fixed the type string to drop the "R_AARCH64_" prefix
>
>  kexec/arch/arm64/kexec-arm64.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
>
> diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
> index 2e8839a..e067a23 100644
> --- a/kexec/arch/arm64/kexec-arm64.c
> +++ b/kexec/arch/arm64/kexec-arm64.c
> @@ -550,6 +550,14 @@ void machine_apply_elf_rel(struct mem_ehdr *ehdr, struct mem_sym *UNUSED(sym),
>  # define R_AARCH64_ADR_PREL_LO21 274
>  #endif
>
> +#if !defined(R_AARCH64_ADR_PREL_PG_HI21)
> +# define R_AARCH64_ADR_PREL_PG_HI21 275
> +#endif
> +
> +#if !defined(R_AARCH64_ADD_ABS_LO12_NC)
> +# define R_AARCH64_ADD_ABS_LO12_NC 277
> +#endif
> +
>  #if !defined(R_AARCH64_JUMP26)
>  # define R_AARCH64_JUMP26 282
>  #endif
> @@ -558,10 +566,15 @@ void machine_apply_elf_rel(struct mem_ehdr *ehdr, struct mem_sym *UNUSED(sym),
>  # define R_AARCH64_CALL26 283
>  #endif
>
> +#if !defined(R_AARCH64_LDST64_ABS_LO12_NC)
> +# define R_AARCH64_LDST64_ABS_LO12_NC 286
> +#endif
> +
>  	uint64_t *loc64;
>  	uint32_t *loc32;
>  	uint64_t *location = (uint64_t *)ptr;
>  	uint64_t data = *location;
> +	uint64_t imm;
>  	const char *type = NULL;
>
>  	switch(r_type) {
> @@ -585,6 +598,19 @@ void machine_apply_elf_rel(struct mem_ehdr *ehdr, struct mem_sym *UNUSED(sym),
>  		*loc32 = cpu_to_le32(le32_to_cpu(*loc32)
>  			+ (((value - address) << 3) & 0xffffe0));
>  		break;
> +	case R_AARCH64_ADR_PREL_PG_HI21:
> +		type = "ADR_PREL_PG_HI21";
> +		imm = ((value & ~0xfff) - (address & ~0xfff)) >> 12;
> +		loc32 = ptr;
> +		*loc32 = cpu_to_le32(le32_to_cpu(*loc32)
> +			+ ((imm & 3) << 29) + ((imm & 0x1ffffc) << (5 - 2)));
> +		break;
> +	case R_AARCH64_ADD_ABS_LO12_NC:
> +		type = "ADD_ABS_LO12_NC";
> +		loc32 = ptr;
> +		*loc32 = cpu_to_le32(le32_to_cpu(*loc32)
> +			+ ((value & 0xfff) << 10));
> +		break;
>  	case R_AARCH64_JUMP26:
>  		type = "JUMP26";
>  		loc32 = ptr;
> @@ -597,6 +623,15 @@ void machine_apply_elf_rel(struct mem_ehdr *ehdr, struct mem_sym *UNUSED(sym),
>  		*loc32 = cpu_to_le32(le32_to_cpu(*loc32)
>  			+ (((value - address) >> 2) & 0x3ffffff));
>  		break;
> +	case R_AARCH64_LDST64_ABS_LO12_NC:
> +		if (value & 7)
> +			die("%s: ERROR Unaligned value: %lx\n", __func__,
> +				value);
> +		type = "LDST64_ABS_LO12_NC";
> +		loc32 = ptr;
> +		*loc32 = cpu_to_le32(le32_to_cpu(*loc32)
> +			+ ((value & 0xff8) << (10 - 3)));
> +		break;
>  	default:
>  		die("%s: ERROR Unknown type: %lu\n", __func__, r_type);
>  		break;
>