Merge the support for live patching on ppc64le using mprofile-kernel.
This branch has also been merged into the livepatching tree for v4.7.
select HAVE_ARCH_SECCOMP_FILTER
select ARCH_HAS_UBSAN_SANITIZE_ALL
select ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
+ select HAVE_LIVEPATCH if HAVE_DYNAMIC_FTRACE_WITH_REGS
config GENERIC_CSUM
def_bool CPU_LITTLE_ENDIAN
bool
source "arch/powerpc/kvm/Kconfig"
+
+source "kernel/livepatch/Kconfig"
--- /dev/null
+/*
+ * livepatch.h - powerpc-specific Kernel Live Patching Core
+ *
+ * Copyright (C) 2015-2016, SUSE, IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _ASM_POWERPC_LIVEPATCH_H
+#define _ASM_POWERPC_LIVEPATCH_H
+
+#include <linux/module.h>
+#include <linux/ftrace.h>
+
+#ifdef CONFIG_LIVEPATCH
+static inline int klp_check_compiler_support(void)
+{
+ return 0;
+}
+
+static inline int klp_write_module_reloc(struct module *mod, unsigned long
+ type, unsigned long loc, unsigned long value)
+{
+ /* This requires infrastructure changes; we need the loadinfos. */
+ return -ENOSYS;
+}
+
+static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+ regs->nip = ip;
+}
+
+#define klp_get_ftrace_location klp_get_ftrace_location
+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.
+ */
+ return ftrace_location_range(faddr, faddr + 16);
+}
+
+static inline void klp_init_thread_info(struct thread_info *ti)
+{
+ /* + 1 to account for STACK_END_MAGIC */
+ ti->livepatch_sp = (unsigned long *)(ti + 1) + 1;
+}
+#else
+static void klp_init_thread_info(struct thread_info *ti) { }
+#endif /* CONFIG_LIVEPATCH */
+
+#endif /* _ASM_POWERPC_LIVEPATCH_H */
int preempt_count; /* 0 => preemptable,
<0 => BUG */
unsigned long local_flags; /* private flags for thread */
-
+#ifdef CONFIG_LIVEPATCH
+ unsigned long *livepatch_sp;
+#endif
/* low level flags - has atomic operations done on it */
unsigned long flags ____cacheline_aligned_in_smp;
};
DEFINE(KSP_LIMIT, offsetof(struct thread_struct, ksp_limit));
#endif /* CONFIG_PPC64 */
+#ifdef CONFIG_LIVEPATCH
+ DEFINE(TI_livepatch_sp, offsetof(struct thread_info, livepatch_sp));
+#endif
+
DEFINE(KSP, offsetof(struct thread_struct, ksp));
DEFINE(PT_REGS, offsetof(struct thread_struct, regs));
#ifdef CONFIG_BOOKE
#include <linux/errno.h>
#include <linux/err.h>
+#include <linux/magic.h>
#include <asm/unistd.h>
#include <asm/processor.h>
#include <asm/page.h>
addi r3,r3,function_trace_op@toc@l
ld r5,0(r3)
+#ifdef CONFIG_LIVEPATCH
+ mr r14,r7 /* remember old NIP */
+#endif
/* Calculate ip from nip-4 into r3 for call below */
subi r3, r7, MCOUNT_INSN_SIZE
/* Load ctr with the possibly modified NIP */
ld r3, _NIP(r1)
mtctr r3
+#ifdef CONFIG_LIVEPATCH
+ cmpd r14,r3 /* has NIP been altered? */
+#endif
/* Restore gprs */
REST_8GPRS(0,r1)
ld r0, LRSAVE(r1)
mtlr r0
+#ifdef CONFIG_LIVEPATCH
+ /* Based on the cmpd above, if the NIP was altered handle livepatch */
+ bne- livepatch_handler
+#endif
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
stdu r1, -112(r1)
.globl ftrace_graph_call
_GLOBAL(ftrace_stub)
blr
+
+#ifdef CONFIG_LIVEPATCH
+ /*
+ * This function runs in the mcount context, between two functions. As
+ * such it can only clobber registers which are volatile and used in
+ * function linkage.
+ *
+ * We get here when a function A, calls another function B, but B has
+ * been live patched with a new function C.
+ *
+ * On entry:
+ * - we have no stack frame and can not allocate one
+ * - LR points back to the original caller (in A)
+ * - CTR holds the new NIP in C
+ * - r0 & r12 are free
+ *
+ * r0 can't be used as the base register for a DS-form load or store, so
+ * we temporarily shuffle r1 (stack pointer) into r0 and then put it back.
+ */
+livepatch_handler:
+ CURRENT_THREAD_INFO(r12, r1)
+
+ /* Save stack pointer into r0 */
+ mr r0, r1
+
+ /* Allocate 3 x 8 bytes */
+ ld r1, TI_livepatch_sp(r12)
+ addi r1, r1, 24
+ std r1, TI_livepatch_sp(r12)
+
+ /* Save toc & real LR on livepatch stack */
+ std r2, -24(r1)
+ mflr r12
+ std r12, -16(r1)
+
+ /* Store stack end marker */
+ lis r12, STACK_END_MAGIC@h
+ ori r12, r12, STACK_END_MAGIC@l
+ std r12, -8(r1)
+
+ /* Restore real stack pointer */
+ mr r1, r0
+
+ /* Put ctr in r12 for global entry and branch there */
+ mfctr r12
+ bctrl
+
+ /*
+ * Now we are returning from the patched function to the original
+ * caller A. We are free to use r0 and r12, and we can use r2 until we
+ * restore it.
+ */
+
+ CURRENT_THREAD_INFO(r12, r1)
+
+ /* Save stack pointer into r0 */
+ mr r0, r1
+
+ ld r1, TI_livepatch_sp(r12)
+
+ /* Check stack marker hasn't been trashed */
+ lis r2, STACK_END_MAGIC@h
+ ori r2, r2, STACK_END_MAGIC@l
+ ld r12, -8(r1)
+1: tdne r12, r2
+ EMIT_BUG_ENTRY 1b, __FILE__, __LINE__ - 1, 0
+
+ /* Restore LR & toc from livepatch stack */
+ ld r12, -16(r1)
+ mtlr r12
+ ld r2, -24(r1)
+
+ /* Pop livepatch stack frame */
+ CURRENT_THREAD_INFO(r12, r0)
+ subi r1, r1, 24
+ std r1, TI_livepatch_sp(r12)
+
+ /* Restore real stack pointer */
+ mr r1, r0
+
+ /* Return to original caller of live patched function */
+ blr
+#endif
+
+
#else
_GLOBAL_TOC(_mcount)
/* Taken from output of objdump from lib64/glibc */
#include <asm/udbg.h>
#include <asm/smp.h>
#include <asm/debug.h>
+#include <asm/livepatch.h>
#ifdef CONFIG_PPC64
#include <asm/paca.h>
memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
tp = softirq_ctx[i];
tp->cpu = i;
+ klp_init_thread_info(tp);
memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
tp = hardirq_ctx[i];
tp->cpu = i;
+ klp_init_thread_info(tp);
}
}
#endif
#include <asm/code-patching.h>
#include <asm/exec.h>
+#include <asm/livepatch.h>
+
#include <linux/kprobes.h>
#include <linux/kdebug.h>
extern void ret_from_kernel_thread(void);
void (*f)(void);
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
+ struct thread_info *ti = task_thread_info(p);
+
+ klp_init_thread_info(ti);
/* Copy registers */
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *) sp;
if (unlikely(p->flags & PF_KTHREAD)) {
/* kernel thread */
- struct thread_info *ti = (void *)task_stack_page(p);
memset(childregs, 0, sizeof(struct pt_regs));
childregs->gpr[1] = sp + sizeof(struct pt_regs);
/* function */
#include <asm/kvm_ppc.h>
#include <asm/hugetlb.h>
#include <asm/epapr_hcalls.h>
+#include <asm/livepatch.h>
#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
limit = min(safe_stack_limit(), ppc64_rma_size);
for_each_possible_cpu(i) {
- unsigned long sp;
- sp = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
- sp += THREAD_SIZE;
- paca[i].emergency_sp = __va(sp);
+ struct thread_info *ti;
+ ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
+ klp_init_thread_info(ti);
+ paca[i].emergency_sp = (void *)ti + THREAD_SIZE;
#ifdef CONFIG_PPC_BOOK3S_64
/* emergency stack for machine check exception handling. */
- sp = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
- sp += THREAD_SIZE;
- paca[i].mc_emergency_sp = __va(sp);
+ ti = __va(memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit));
+ klp_init_thread_info(ti);
+ paca[i].mc_emergency_sp = (void *)ti + THREAD_SIZE;
#endif
}
}
if (ppc_md.panic)
setup_panic();
+ klp_init_thread_info(&init_thread_info);
+
init_mm.start_code = (unsigned long)_stext;
init_mm.end_code = (unsigned long) _etext;
init_mm.end_data = (unsigned long) _edata;
int ftrace_test_record(struct dyn_ftrace *rec, int enable);
void ftrace_run_stop_machine(int command);
unsigned long ftrace_location(unsigned long ip);
+unsigned long ftrace_location_range(unsigned long start, unsigned long end);
unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec);
unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec);
rcu_read_unlock();
}
+/*
+ * Convert a function address into the appropriate ftrace location.
+ *
+ * Usually this is just the address of the function, but on some architectures
+ * it's more complicated so allow them to provide a custom behaviour.
+ */
+#ifndef klp_get_ftrace_location
+static unsigned long klp_get_ftrace_location(unsigned long faddr)
+{
+ return faddr;
+}
+#endif
+
static void klp_disable_func(struct klp_func *func)
{
struct klp_ops *ops;
return;
if (list_is_singular(&ops->func_stack)) {
+ unsigned long ftrace_loc;
+
+ ftrace_loc = klp_get_ftrace_location(func->old_addr);
+ if (WARN_ON(!ftrace_loc))
+ return;
+
WARN_ON(unregister_ftrace_function(&ops->fops));
- WARN_ON(ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0));
+ WARN_ON(ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0));
list_del_rcu(&func->stack_node);
list_del(&ops->node);
ops = klp_find_ops(func->old_addr);
if (!ops) {
+ unsigned long ftrace_loc;
+
+ ftrace_loc = klp_get_ftrace_location(func->old_addr);
+ if (!ftrace_loc) {
+ pr_err("failed to find location for function '%s'\n",
+ func->old_name);
+ return -EINVAL;
+ }
+
ops = kzalloc(sizeof(*ops), GFP_KERNEL);
if (!ops)
return -ENOMEM;
INIT_LIST_HEAD(&ops->func_stack);
list_add_rcu(&func->stack_node, &ops->func_stack);
- ret = ftrace_set_filter_ip(&ops->fops, func->old_addr, 0, 0);
+ ret = ftrace_set_filter_ip(&ops->fops, ftrace_loc, 0, 0);
if (ret) {
pr_err("failed to set ftrace filter for function '%s' (%d)\n",
func->old_name, ret);
if (ret) {
pr_err("failed to register ftrace handler for function '%s' (%d)\n",
func->old_name, ret);
- ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0);
+ ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0);
goto err;
}
return 0;
}
-static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
+/**
+ * ftrace_location_range - return the first address of a traced location
+ * if it touches the given ip range
+ * @start: start of range to search.
+ * @end: end of range to search (inclusive). @end points to the last byte
+ * to check.
+ *
+ * Returns rec->ip if the related ftrace location is a least partly within
+ * the given address range. That is, the first address of the instruction
+ * that is either a NOP or call to the function tracer. It checks the ftrace
+ * internal tables to determine if the address belongs or not.
+ */
+unsigned long ftrace_location_range(unsigned long start, unsigned long end)
{
struct ftrace_page *pg;
struct dyn_ftrace *rec;
projects / linux-beck.git / commitdiff