diff options
| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-10-28 17:15:27 -0400 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-11-13 12:15:28 -0500 |
| commit | 2860cd8a235375df3c8ec8039d9fe5eb2f658b86 (patch) | |
| tree | fdc9022ea4057f4d410d7b907b158d7cbb8787e8 /kernel/livepatch | |
| parent | 02a474ca266a47ea8f4d5a11f4ffa120f83730ad (diff) | |
livepatch: Use the default ftrace_ops instead of REGS when ARGS is available
When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS is available, the ftrace call
will be able to set the ip of the calling function. This will improve the
performance of live kernel patching where it does not need all the regs to
be stored just to change the instruction pointer.
If all archs that support live kernel patching also support
HAVE_DYNAMIC_FTRACE_WITH_ARGS, then the architecture specific function
klp_arch_set_pc() could be made generic.
It is possible that an arch can support HAVE_DYNAMIC_FTRACE_WITH_ARGS but
not HAVE_DYNAMIC_FTRACE_WITH_REGS and then have access to live patching.
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: live-patching@vger.kernel.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/livepatch')
| -rw-r--r-- | kernel/livepatch/Kconfig | 2 | ||||
| -rw-r--r-- | kernel/livepatch/patch.c | 9 |
2 files changed, 6 insertions, 5 deletions
diff --git a/kernel/livepatch/Kconfig b/kernel/livepatch/Kconfig index 54102deb50ba..53d51ed619a3 100644 --- a/kernel/livepatch/Kconfig +++ b/kernel/livepatch/Kconfig @@ -6,7 +6,7 @@ config HAVE_LIVEPATCH config LIVEPATCH bool "Kernel Live Patching" - depends on DYNAMIC_FTRACE_WITH_REGS + depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS depends on MODULES depends on SYSFS depends on KALLSYMS_ALL diff --git a/kernel/livepatch/patch.c b/kernel/livepatch/patch.c index f89f9e7e9b07..e8029aea67f1 100644 --- a/kernel/livepatch/patch.c +++ b/kernel/livepatch/patch.c @@ -42,7 +42,6 @@ static void notrace klp_ftrace_handler(unsigned long ip, struct ftrace_ops *fops, struct ftrace_regs *fregs) { - struct pt_regs *regs = ftrace_get_regs(fregs); struct klp_ops *ops; struct klp_func *func; int patch_state; @@ -118,7 +117,7 @@ static void notrace klp_ftrace_handler(unsigned long ip, if (func->nop) goto unlock; - klp_arch_set_pc(regs, (unsigned long)func->new_func); + klp_arch_set_pc(fregs, (unsigned long)func->new_func); unlock: preempt_enable_notrace(); @@ -200,8 +199,10 @@ static int klp_patch_func(struct klp_func *func) return -ENOMEM; ops->fops.func = klp_ftrace_handler; - ops->fops.flags = FTRACE_OPS_FL_SAVE_REGS | - FTRACE_OPS_FL_DYNAMIC | + ops->fops.flags = FTRACE_OPS_FL_DYNAMIC | +#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS + FTRACE_OPS_FL_SAVE_REGS | +#endif FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_PERMANENT; |