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powerpc/ftrace: Add support for livepatch to PPC32

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PPC64 needs some special logic to properly set up the TOC.
See commit 85baa09549 ("powerpc/livepatch: Add live patching support
on ppc64le") for details.

PPC32 doesn't have TOC so it doesn't need that logic, so adding
LIVEPATCH support is straight forward.

Add CONFIG_LIVEPATCH_64 and move livepatch stack logic into that item.

Livepatch sample modules all work.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/63cb094125b6a6038c65eeac2abaabbabe63addd.1640017960.git.christophe.leroy@csgroup.eu
This commit is contained in:
Christophe Leroy 2021-12-20 16:38:12 +00:00 committed by Michael Ellerman
parent 0c850965d6
commit a4520b2527
4 changed files with 12 additions and 6 deletions
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6
arch/powerpc/Kconfig
View File

@ -9,6 +9,10 @@ config 64BIT
bool
default y if PPC64
config LIVEPATCH_64
def_bool PPC64
depends on LIVEPATCH
config MMU
bool
default y
@ -221,7 +225,7 @@ config PPC
select HAVE_KPROBES_ON_FTRACE
select HAVE_KRETPROBES
select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
select HAVE_LIVEPATCH if HAVE_DYNAMIC_FTRACE_WITH_REGS && PPC64
select HAVE_LIVEPATCH if HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI if PERF_EVENTS || (PPC64 && PPC_BOOK3S)
select HAVE_OPTPROBES

8
arch/powerpc/include/asm/livepatch.h
View File

@ -23,12 +23,14 @@ static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip)
static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
{
/*
* Live patch works only with -mprofile-kernel on PPC. In this case,
* the ftrace location is always within the first 16 bytes.
* Live patch works on PPC32 and only with -mprofile-kernel on PPC64. In
* both cases, the ftrace location is always within the first 16 bytes.
*/
return ftrace_location_range(faddr, faddr + 16);
}
#endif /* CONFIG_LIVEPATCH */
#ifdef CONFIG_LIVEPATCH_64
static inline void klp_init_thread_info(struct task_struct *p)
{
/* + 1 to account for STACK_END_MAGIC */
@ -36,6 +38,6 @@ static inline void klp_init_thread_info(struct task_struct *p)
}
#else
static inline void klp_init_thread_info(struct task_struct *p) { }
#endif /* CONFIG_LIVEPATCH */
#endif
#endif /* _ASM_POWERPC_LIVEPATCH_H */

2
arch/powerpc/include/asm/thread_info.h
View File

@ -51,7 +51,7 @@ struct thread_info {
unsigned int cpu;
#endif
unsigned long local_flags; /* private flags for thread */
#ifdef CONFIG_LIVEPATCH
#ifdef CONFIG_LIVEPATCH_64
unsigned long *livepatch_sp;
#endif
#if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(CONFIG_PPC32)

2
arch/powerpc/kernel/asm-offsets.c
View File

@ -94,7 +94,7 @@ int main(void)
OFFSET(TASK_CPU, task_struct, thread_info.cpu);
#endif
#ifdef CONFIG_LIVEPATCH
#ifdef CONFIG_LIVEPATCH_64
OFFSET(TI_livepatch_sp, thread_info, livepatch_sp);
#endif