luck/tmp_suning_uos_patched
1
0
Fork 1
Code Issues Pull Requests Packages Projects Releases Wiki Activity

powerpc: Add ppc_inst_as_u64()

Browse Source 
The code patching code wants to get the value of a struct ppc_inst as
a u64 when the instruction is prefixed, so we can pass the u64 down to
__put_user_asm() and write it with a single store.

The optprobes code wants to load a struct ppc_inst as an immediate
into a register so it is useful to have it as a u64 to use the
existing helper function.

Currently this is a bit awkward because the value differs based on the
CPU endianness, so add a helper to do the conversion.

This fixes the usage in arch_prepare_optimized_kprobe() which was
previously incorrect on big endian.

Fixes: 650b55b707 ("powerpc: Add prefixed instructions to instruction data type")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Jordan Niethe <jniethe5@gmail.com>
Link: https://lore.kernel.org/r/20200526072630.2487363-1-mpe@ellerman.id.au
This commit is contained in:
Michael Ellerman 2020-05-26 17:26:30 +10:00
parent c5ff46d69c
commit 16ef9767e4
3 changed files with 11 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
arch/powerpc/include/asm/inst.h
View File

@ -113,6 +113,15 @@ static inline struct ppc_inst *ppc_inst_next(void *location, struct ppc_inst *va
return location + ppc_inst_len(tmp);
}
static inline u64 ppc_inst_as_u64(struct ppc_inst x)
{
#ifdef CONFIG_CPU_LITTLE_ENDIAN
return (u64)ppc_inst_suffix(x) << 32 | ppc_inst_val(x);
#else
return (u64)ppc_inst_val(x) << 32 | ppc_inst_suffix(x);
#endif
}
int probe_user_read_inst(struct ppc_inst *inst,
struct ppc_inst __user *nip);

3
arch/powerpc/kernel/optprobes.c
View File

@ -283,8 +283,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
* 3. load instruction to be emulated into relevant register, and
*/
temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
patch_imm64_load_insns(ppc_inst_val(temp) | ((u64)ppc_inst_suffix(temp) << 32),
4, buff + TMPL_INSN_IDX);
patch_imm64_load_insns(ppc_inst_as_u64(temp), 4, buff + TMPL_INSN_IDX);
/*
* 4. branch back from trampoline

8
arch/powerpc/lib/code-patching.c
View File

@ -27,13 +27,7 @@ static int __patch_instruction(struct ppc_inst *exec_addr, struct ppc_inst instr
if (!ppc_inst_prefixed(instr)) {
__put_user_asm(ppc_inst_val(instr), patch_addr, err, "stw");
} else {
#ifdef CONFIG_CPU_LITTLE_ENDIAN
__put_user_asm((u64)ppc_inst_suffix(instr) << 32 |
ppc_inst_val(instr), patch_addr, err, "std");
#else
__put_user_asm((u64)ppc_inst_val(instr) << 32 |
ppc_inst_suffix(instr), patch_addr, err, "std");
#endif
__put_user_asm(ppc_inst_as_u64(instr), patch_addr, err, "std");
}
if (err)