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Diffstat (limited to '')
| -rw-r--r-- | arch/microblaze/kernel/ftrace.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c new file mode 100644 index 000000000..188749d62 --- /dev/null +++ b/arch/microblaze/kernel/ftrace.c @@ -0,0 +1,217 @@ +/* + * Ftrace support for Microblaze. + * + * Copyright (C) 2009 Michal Simek <monstr@monstr.eu> + * Copyright (C) 2009 PetaLogix + * + * Based on MIPS and PowerPC ftrace code + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include <asm/cacheflush.h> +#include <linux/ftrace.h> + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +/* + * Hook the return address and push it in the stack of return addrs + * in current thread info. + */ +void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) +{ + unsigned long old; + int faulted; + unsigned long return_hooker = (unsigned long) + &return_to_handler; + + if (unlikely(ftrace_graph_is_dead())) + return; + + if (unlikely(atomic_read(¤t->tracing_graph_pause))) + return; + + /* + * Protect against fault, even if it shouldn't + * happen. This tool is too much intrusive to + * ignore such a protection. + */ + asm volatile(" 1: lwi %0, %2, 0;" \ + "2: swi %3, %2, 0;" \ + " addik %1, r0, 0;" \ + "3:" \ + " .section .fixup, \"ax\";" \ + "4: brid 3b;" \ + " addik %1, r0, 1;" \ + " .previous;" \ + " .section __ex_table,\"a\";" \ + " .word 1b,4b;" \ + " .word 2b,4b;" \ + " .previous;" \ + : "=&r" (old), "=r" (faulted) + : "r" (parent), "r" (return_hooker) + ); + + flush_dcache_range((u32)parent, (u32)parent + 4); + flush_icache_range((u32)parent, (u32)parent + 4); + + if (unlikely(faulted)) { + ftrace_graph_stop(); + WARN_ON(1); + return; + } + + if (function_graph_enter(old, self_addr, 0, NULL)) + *parent = old; +} +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#ifdef CONFIG_DYNAMIC_FTRACE +/* save value to addr - it is save to do it in asm */ +static int ftrace_modify_code(unsigned long addr, unsigned int value) +{ + int faulted = 0; + + __asm__ __volatile__(" 1: swi %2, %1, 0;" \ + " addik %0, r0, 0;" \ + "2:" \ + " .section .fixup, \"ax\";" \ + "3: brid 2b;" \ + " addik %0, r0, 1;" \ + " .previous;" \ + " .section __ex_table,\"a\";" \ + " .word 1b,3b;" \ + " .previous;" \ + : "=r" (faulted) + : "r" (addr), "r" (value) + ); + + if (unlikely(faulted)) + return -EFAULT; + + flush_dcache_range(addr, addr + 4); + flush_icache_range(addr, addr + 4); + + return 0; +} + +#define MICROBLAZE_NOP 0x80000000 +#define MICROBLAZE_BRI 0xb800000C + +static unsigned int recorded; /* if save was or not */ +static unsigned int imm; /* saving whole imm instruction */ + +/* There are two approaches howto solve ftrace_make nop function - look below */ +#undef USE_FTRACE_NOP + +#ifdef USE_FTRACE_NOP +static unsigned int bralid; /* saving whole bralid instruction */ +#endif + +int ftrace_make_nop(struct module *mod, + struct dyn_ftrace *rec, unsigned long addr) +{ + /* we have this part of code which we are working with + * b000c000 imm -16384 + * b9fc8e30 bralid r15, -29136 // c0008e30 <_mcount> + * 80000000 or r0, r0, r0 + * + * The first solution (!USE_FTRACE_NOP-could be called branch solution) + * b000c000 bri 12 (0xC - jump to any other instruction) + * b9fc8e30 bralid r15, -29136 // c0008e30 <_mcount> + * 80000000 or r0, r0, r0 + * any other instruction + * + * The second solution (USE_FTRACE_NOP) - no jump just nops + * 80000000 or r0, r0, r0 + * 80000000 or r0, r0, r0 + * 80000000 or r0, r0, r0 + */ + int ret = 0; + + if (recorded == 0) { + recorded = 1; + imm = *(unsigned int *)rec->ip; + pr_debug("%s: imm:0x%x\n", __func__, imm); +#ifdef USE_FTRACE_NOP + bralid = *(unsigned int *)(rec->ip + 4); + pr_debug("%s: bralid 0x%x\n", __func__, bralid); +#endif /* USE_FTRACE_NOP */ + } + +#ifdef USE_FTRACE_NOP + ret = ftrace_modify_code(rec->ip, MICROBLAZE_NOP); + ret += ftrace_modify_code(rec->ip + 4, MICROBLAZE_NOP); +#else /* USE_FTRACE_NOP */ + ret = ftrace_modify_code(rec->ip, MICROBLAZE_BRI); +#endif /* USE_FTRACE_NOP */ + return ret; +} + +/* I believe that first is called ftrace_make_nop before this function */ +int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) +{ + int ret; + pr_debug("%s: addr:0x%x, rec->ip: 0x%x, imm:0x%x\n", + __func__, (unsigned int)addr, (unsigned int)rec->ip, imm); + ret = ftrace_modify_code(rec->ip, imm); +#ifdef USE_FTRACE_NOP + pr_debug("%s: bralid:0x%x\n", __func__, bralid); + ret += ftrace_modify_code(rec->ip + 4, bralid); +#endif /* USE_FTRACE_NOP */ + return ret; +} + +int ftrace_update_ftrace_func(ftrace_func_t func) +{ + unsigned long ip = (unsigned long)(&ftrace_call); + unsigned int upper = (unsigned int)func; + unsigned int lower = (unsigned int)func; + int ret = 0; + + /* create proper saving to ftrace_call poll */ + upper = 0xb0000000 + (upper >> 16); /* imm func_upper */ + lower = 0x32800000 + (lower & 0xFFFF); /* addik r20, r0, func_lower */ + + pr_debug("%s: func=0x%x, ip=0x%x, upper=0x%x, lower=0x%x\n", + __func__, (unsigned int)func, (unsigned int)ip, upper, lower); + + /* save upper and lower code */ + ret = ftrace_modify_code(ip, upper); + ret += ftrace_modify_code(ip + 4, lower); + + /* We just need to replace the rtsd r15, 8 with NOP */ + ret += ftrace_modify_code((unsigned long)&ftrace_caller, + MICROBLAZE_NOP); + + return ret; +} + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +unsigned int old_jump; /* saving place for jump instruction */ + +int ftrace_enable_ftrace_graph_caller(void) +{ + unsigned int ret; + unsigned long ip = (unsigned long)(&ftrace_call_graph); + + old_jump = *(unsigned int *)ip; /* save jump over instruction */ + ret = ftrace_modify_code(ip, MICROBLAZE_NOP); + + pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump); + return ret; +} + +int ftrace_disable_ftrace_graph_caller(void) +{ + unsigned int ret; + unsigned long ip = (unsigned long)(&ftrace_call_graph); + + ret = ftrace_modify_code(ip, old_jump); + + pr_debug("%s\n", __func__); + return ret; +} +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ +#endif /* CONFIG_DYNAMIC_FTRACE */ |