v4.19.13 snapshot.
diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c
new file mode 100644
index 0000000..b122cbb
--- /dev/null
+++ b/arch/mips/kernel/ftrace.c
@@ -0,0 +1,417 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Code for replacing ftrace calls with jumps.
+ *
+ * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2009, 2010 DSLab, Lanzhou University, China
+ * Author: Wu Zhangjin <wuzhangjin@gmail.com>
+ *
+ * Thanks goes to Steven Rostedt for writing the original x86 version.
+ */
+
+#include <linux/uaccess.h>
+#include <linux/init.h>
+#include <linux/ftrace.h>
+#include <linux/syscalls.h>
+
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/cacheflush.h>
+#include <asm/syscall.h>
+#include <asm/uasm.h>
+#include <asm/unistd.h>
+
+#include <asm-generic/sections.h>
+
+#if defined(KBUILD_MCOUNT_RA_ADDRESS) && defined(CONFIG_32BIT)
+#define MCOUNT_OFFSET_INSNS 5
+#else
+#define MCOUNT_OFFSET_INSNS 4
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+/* Arch override because MIPS doesn't need to run this from stop_machine() */
+void arch_ftrace_update_code(int command)
+{
+ ftrace_modify_all_code(command);
+}
+
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+#define JAL 0x0c000000 /* jump & link: ip --> ra, jump to target */
+#define ADDR_MASK 0x03ffffff /* op_code|addr : 31...26|25 ....0 */
+#define JUMP_RANGE_MASK ((1UL << 28) - 1)
+
+#define INSN_NOP 0x00000000 /* nop */
+#define INSN_JAL(addr) \
+ ((unsigned int)(JAL | (((addr) >> 2) & ADDR_MASK)))
+
+static unsigned int insn_jal_ftrace_caller __read_mostly;
+static unsigned int insn_la_mcount[2] __read_mostly;
+static unsigned int insn_j_ftrace_graph_caller __maybe_unused __read_mostly;
+
+static inline void ftrace_dyn_arch_init_insns(void)
+{
+ u32 *buf;
+ unsigned int v1;
+
+ /* la v1, _mcount */
+ v1 = 3;
+ buf = (u32 *)&insn_la_mcount[0];
+ UASM_i_LA(&buf, v1, MCOUNT_ADDR);
+
+ /* jal (ftrace_caller + 8), jump over the first two instruction */
+ buf = (u32 *)&insn_jal_ftrace_caller;
+ uasm_i_jal(&buf, (FTRACE_ADDR + 8) & JUMP_RANGE_MASK);
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ /* j ftrace_graph_caller */
+ buf = (u32 *)&insn_j_ftrace_graph_caller;
+ uasm_i_j(&buf, (unsigned long)ftrace_graph_caller & JUMP_RANGE_MASK);
+#endif
+}
+
+static int ftrace_modify_code(unsigned long ip, unsigned int new_code)
+{
+ int faulted;
+ mm_segment_t old_fs;
+
+ /* *(unsigned int *)ip = new_code; */
+ safe_store_code(new_code, ip, faulted);
+
+ if (unlikely(faulted))
+ return -EFAULT;
+
+ old_fs = get_fs();
+ set_fs(get_ds());
+ flush_icache_range(ip, ip + 8);
+ set_fs(old_fs);
+
+ return 0;
+}
+
+#ifndef CONFIG_64BIT
+static int ftrace_modify_code_2(unsigned long ip, unsigned int new_code1,
+ unsigned int new_code2)
+{
+ int faulted;
+ mm_segment_t old_fs;
+
+ safe_store_code(new_code1, ip, faulted);
+ if (unlikely(faulted))
+ return -EFAULT;
+
+ ip += 4;
+ safe_store_code(new_code2, ip, faulted);
+ if (unlikely(faulted))
+ return -EFAULT;
+
+ ip -= 4;
+ old_fs = get_fs();
+ set_fs(get_ds());
+ flush_icache_range(ip, ip + 8);
+ set_fs(old_fs);
+
+ return 0;
+}
+
+static int ftrace_modify_code_2r(unsigned long ip, unsigned int new_code1,
+ unsigned int new_code2)
+{
+ int faulted;
+ mm_segment_t old_fs;
+
+ ip += 4;
+ safe_store_code(new_code2, ip, faulted);
+ if (unlikely(faulted))
+ return -EFAULT;
+
+ ip -= 4;
+ safe_store_code(new_code1, ip, faulted);
+ if (unlikely(faulted))
+ return -EFAULT;
+
+ old_fs = get_fs();
+ set_fs(get_ds());
+ flush_icache_range(ip, ip + 8);
+ set_fs(old_fs);
+
+ return 0;
+}
+#endif
+
+/*
+ * The details about the calling site of mcount on MIPS
+ *
+ * 1. For kernel:
+ *
+ * move at, ra
+ * jal _mcount --> nop
+ * sub sp, sp, 8 --> nop (CONFIG_32BIT)
+ *
+ * 2. For modules:
+ *
+ * 2.1 For KBUILD_MCOUNT_RA_ADDRESS and CONFIG_32BIT
+ *
+ * lui v1, hi_16bit_of_mcount --> b 1f (0x10000005)
+ * addiu v1, v1, low_16bit_of_mcount --> nop (CONFIG_32BIT)
+ * move at, ra
+ * move $12, ra_address
+ * jalr v1
+ * sub sp, sp, 8
+ * 1: offset = 5 instructions
+ * 2.2 For the Other situations
+ *
+ * lui v1, hi_16bit_of_mcount --> b 1f (0x10000004)
+ * addiu v1, v1, low_16bit_of_mcount --> nop (CONFIG_32BIT)
+ * move at, ra
+ * jalr v1
+ * nop | move $12, ra_address | sub sp, sp, 8
+ * 1: offset = 4 instructions
+ */
+
+#define INSN_B_1F (0x10000000 | MCOUNT_OFFSET_INSNS)
+
+int ftrace_make_nop(struct module *mod,
+ struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned int new;
+ unsigned long ip = rec->ip;
+
+ /*
+ * If ip is in kernel space, no long call, otherwise, long call is
+ * needed.
+ */
+ new = core_kernel_text(ip) ? INSN_NOP : INSN_B_1F;
+#ifdef CONFIG_64BIT
+ return ftrace_modify_code(ip, new);
+#else
+ /*
+ * On 32 bit MIPS platforms, gcc adds a stack adjust
+ * instruction in the delay slot after the branch to
+ * mcount and expects mcount to restore the sp on return.
+ * This is based on a legacy API and does nothing but
+ * waste instructions so it's being removed at runtime.
+ */
+ return ftrace_modify_code_2(ip, new, INSN_NOP);
+#endif
+}
+
+int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned int new;
+ unsigned long ip = rec->ip;
+
+ new = core_kernel_text(ip) ? insn_jal_ftrace_caller : insn_la_mcount[0];
+
+#ifdef CONFIG_64BIT
+ return ftrace_modify_code(ip, new);
+#else
+ return ftrace_modify_code_2r(ip, new, core_kernel_text(ip) ?
+ INSN_NOP : insn_la_mcount[1]);
+#endif
+}
+
+#define FTRACE_CALL_IP ((unsigned long)(&ftrace_call))
+
+int ftrace_update_ftrace_func(ftrace_func_t func)
+{
+ unsigned int new;
+
+ new = INSN_JAL((unsigned long)func);
+
+ return ftrace_modify_code(FTRACE_CALL_IP, new);
+}
+
+int __init ftrace_dyn_arch_init(void)
+{
+ /* Encode the instructions when booting */
+ ftrace_dyn_arch_init_insns();
+
+ /* Remove "b ftrace_stub" to ensure ftrace_caller() is executed */
+ ftrace_modify_code(MCOUNT_ADDR, INSN_NOP);
+
+ return 0;
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+extern void ftrace_graph_call(void);
+#define FTRACE_GRAPH_CALL_IP ((unsigned long)(&ftrace_graph_call))
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+ return ftrace_modify_code(FTRACE_GRAPH_CALL_IP,
+ insn_j_ftrace_graph_caller);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+ return ftrace_modify_code(FTRACE_GRAPH_CALL_IP, INSN_NOP);
+}
+
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifndef KBUILD_MCOUNT_RA_ADDRESS
+
+#define S_RA_SP (0xafbf << 16) /* s{d,w} ra, offset(sp) */
+#define S_R_SP (0xafb0 << 16) /* s{d,w} R, offset(sp) */
+#define OFFSET_MASK 0xffff /* stack offset range: 0 ~ PT_SIZE */
+
+unsigned long ftrace_get_parent_ra_addr(unsigned long self_ra, unsigned long
+ old_parent_ra, unsigned long parent_ra_addr, unsigned long fp)
+{
+ unsigned long sp, ip, tmp;
+ unsigned int code;
+ int faulted;
+
+ /*
+ * For module, move the ip from the return address after the
+ * instruction "lui v1, hi_16bit_of_mcount"(offset is 24), but for
+ * kernel, move after the instruction "move ra, at"(offset is 16)
+ */
+ ip = self_ra - (core_kernel_text(self_ra) ? 16 : 24);
+
+ /*
+ * search the text until finding the non-store instruction or "s{d,w}
+ * ra, offset(sp)" instruction
+ */
+ do {
+ /* get the code at "ip": code = *(unsigned int *)ip; */
+ safe_load_code(code, ip, faulted);
+
+ if (unlikely(faulted))
+ return 0;
+ /*
+ * If we hit the non-store instruction before finding where the
+ * ra is stored, then this is a leaf function and it does not
+ * store the ra on the stack
+ */
+ if ((code & S_R_SP) != S_R_SP)
+ return parent_ra_addr;
+
+ /* Move to the next instruction */
+ ip -= 4;
+ } while ((code & S_RA_SP) != S_RA_SP);
+
+ sp = fp + (code & OFFSET_MASK);
+
+ /* tmp = *(unsigned long *)sp; */
+ safe_load_stack(tmp, sp, faulted);
+ if (unlikely(faulted))
+ return 0;
+
+ if (tmp == old_parent_ra)
+ return sp;
+ return 0;
+}
+
+#endif /* !KBUILD_MCOUNT_RA_ADDRESS */
+
+/*
+ * Hook the return address and push it in the stack of return addrs
+ * in current thread info.
+ */
+void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra,
+ unsigned long fp)
+{
+ unsigned long old_parent_ra;
+ unsigned long return_hooker = (unsigned long)
+ &return_to_handler;
+ int faulted, insns;
+
+ if (unlikely(ftrace_graph_is_dead()))
+ return;
+
+ if (unlikely(atomic_read(¤t->tracing_graph_pause)))
+ return;
+
+ /*
+ * "parent_ra_addr" is the stack address saved the return address of
+ * the caller of _mcount.
+ *
+ * if the gcc < 4.5, a leaf function does not save the return address
+ * in the stack address, so, we "emulate" one in _mcount's stack space,
+ * and hijack it directly, but for a non-leaf function, it save the
+ * return address to the its own stack space, we can not hijack it
+ * directly, but need to find the real stack address,
+ * ftrace_get_parent_addr() does it!
+ *
+ * if gcc>= 4.5, with the new -mmcount-ra-address option, for a
+ * non-leaf function, the location of the return address will be saved
+ * to $12 for us, and for a leaf function, only put a zero into $12. we
+ * do it in ftrace_graph_caller of mcount.S.
+ */
+
+ /* old_parent_ra = *parent_ra_addr; */
+ safe_load_stack(old_parent_ra, parent_ra_addr, faulted);
+ if (unlikely(faulted))
+ goto out;
+#ifndef KBUILD_MCOUNT_RA_ADDRESS
+ parent_ra_addr = (unsigned long *)ftrace_get_parent_ra_addr(self_ra,
+ old_parent_ra, (unsigned long)parent_ra_addr, fp);
+ /*
+ * If fails when getting the stack address of the non-leaf function's
+ * ra, stop function graph tracer and return
+ */
+ if (parent_ra_addr == NULL)
+ goto out;
+#endif
+ /* *parent_ra_addr = return_hooker; */
+ safe_store_stack(return_hooker, parent_ra_addr, faulted);
+ if (unlikely(faulted))
+ goto out;
+
+ /*
+ * Get the recorded ip of the current mcount calling site in the
+ * __mcount_loc section, which will be used to filter the function
+ * entries configured through the tracing/set_graph_function interface.
+ */
+
+ insns = core_kernel_text(self_ra) ? 2 : MCOUNT_OFFSET_INSNS + 1;
+ self_ra -= (MCOUNT_INSN_SIZE * insns);
+
+ if (function_graph_enter(old_parent_ra, self_ra, fp, NULL))
+ *parent_ra_addr = old_parent_ra;
+ return;
+out:
+ ftrace_graph_stop();
+ WARN_ON(1);
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+#ifdef CONFIG_FTRACE_SYSCALLS
+
+#ifdef CONFIG_32BIT
+unsigned long __init arch_syscall_addr(int nr)
+{
+ return (unsigned long)sys_call_table[nr - __NR_O32_Linux];
+}
+#endif
+
+#ifdef CONFIG_64BIT
+
+unsigned long __init arch_syscall_addr(int nr)
+{
+#ifdef CONFIG_MIPS32_N32
+ if (nr >= __NR_N32_Linux && nr <= __NR_N32_Linux + __NR_N32_Linux_syscalls)
+ return (unsigned long)sysn32_call_table[nr - __NR_N32_Linux];
+#endif
+ if (nr >= __NR_64_Linux && nr <= __NR_64_Linux + __NR_64_Linux_syscalls)
+ return (unsigned long)sys_call_table[nr - __NR_64_Linux];
+#ifdef CONFIG_MIPS32_O32
+ if (nr >= __NR_O32_Linux && nr <= __NR_O32_Linux + __NR_O32_Linux_syscalls)
+ return (unsigned long)sys32_call_table[nr - __NR_O32_Linux];
+#endif
+
+ return (unsigned long) &sys_ni_syscall;
+}
+#endif
+
+#endif /* CONFIG_FTRACE_SYSCALLS */