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Re: [Xen-devel] [PATCH v5 05/16] livepatch: Initial ARM64 support.
On 09/21/2016 06:32 PM, Konrad Rzeszutek Wilk wrote:
snip
+
+void arch_livepatch_revert(const struct livepatch_func *func)
+{
+ uint32_t *new_ptr;
+ unsigned int i, len;
+
+ new_ptr = func->old_addr - (void *)_start + vmap_of_xen_text;
+ len = livepatch_insn_len(func) / sizeof(uint32_t);
+ for ( i = 0; i < len; i++ )
+ {
+ uint32_t insn;
+
+ memcpy(&insn, func->opaque + (i * sizeof(uint32_t)),
ARCH_PATCH_INSN_SIZE);
+ /* PATCH! */
+ *(new_ptr + i) = insn;
+ }
Why is this done in a loop? Can't we just memcpy
livepatch_insn_len(func) bytes into *new_ptr?
+}
+
+int arch_livepatch_verify_elf(const struct livepatch_elf *elf)
+{
+ const Elf_Ehdr *hdr = elf->hdr;
+
+ if ( hdr->e_machine != EM_AARCH64 ||
+ hdr->e_ident[EI_CLASS] != ELFCLASS64 )
+ {
+ dprintk(XENLOG_ERR, LIVEPATCH "%s: Unsupported ELF Machine type!\n",
+ elf->name);
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
snip
int arch_livepatch_verify_func(const struct livepatch_func *func)
{
- return -ENOSYS;
-}
+ /* If NOPing only do up to maximum amount we can put in the ->opaque. */
+ if ( !func->new_addr && func->new_size > sizeof(func->opaque) &&
+ func->new_size % ARCH_PATCH_INSN_SIZE )
+ return -EOPNOTSUPP;
Maybe I'm misunderstanding, but shouldn't this be ( !func->new_addr &&
(func->new_size > sizeof(func->opaque) || func->new_size %
ARCH_PATCH_INSN_SIZE) ) ?
--
Ross Lagerwall
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