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Subject[ammarfaizi2-block:tglx/devel/depthtracking 58/59] arch/x86/net/bpf_jit_comp.c:2103:40: error: use of undeclared identifier '__fentry__'
tree:   https://github.com/ammarfaizi2/linux-block tglx/devel/depthtracking
head: 9bbf33b92f4c755dd56f4d9bc1b40e94fdd1fff7
commit: 5f5bcd6ccea80ee1fa71477dbf80d43d9cbbf30a [58/59] x86/ftrace: Make it call depth tracking aware
config: x86_64-randconfig-a013-20220815 (https://download.01.org/0day-ci/archive/20220817/202208170727.cRWzeoJx-lkp@intel.com/config)
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 6afcc4a459ead8809a0d6d9b4bf7b64bcc13582b)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/ammarfaizi2/linux-block/commit/5f5bcd6ccea80ee1fa71477dbf80d43d9cbbf30a
git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
git fetch --no-tags ammarfaizi2-block tglx/devel/depthtracking
git checkout 5f5bcd6ccea80ee1fa71477dbf80d43d9cbbf30a
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> arch/x86/net/bpf_jit_comp.c:2103:40: error: use of undeclared identifier '__fentry__'
x86_call_depth_emit_accounting(&prog, __fentry__);
^
1 error generated.


vim +/__fentry__ +2103 arch/x86/net/bpf_jit_comp.c

1970
1971 /* Example:
1972 * __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
1973 * its 'struct btf_func_model' will be nr_args=2
1974 * The assembly code when eth_type_trans is executing after trampoline:
1975 *
1976 * push rbp
1977 * mov rbp, rsp
1978 * sub rsp, 16 // space for skb and dev
1979 * push rbx // temp regs to pass start time
1980 * mov qword ptr [rbp - 16], rdi // save skb pointer to stack
1981 * mov qword ptr [rbp - 8], rsi // save dev pointer to stack
1982 * call __bpf_prog_enter // rcu_read_lock and preempt_disable
1983 * mov rbx, rax // remember start time in bpf stats are enabled
1984 * lea rdi, [rbp - 16] // R1==ctx of bpf prog
1985 * call addr_of_jited_FENTRY_prog
1986 * movabsq rdi, 64bit_addr_of_struct_bpf_prog // unused if bpf stats are off
1987 * mov rsi, rbx // prog start time
1988 * call __bpf_prog_exit // rcu_read_unlock, preempt_enable and stats math
1989 * mov rdi, qword ptr [rbp - 16] // restore skb pointer from stack
1990 * mov rsi, qword ptr [rbp - 8] // restore dev pointer from stack
1991 * pop rbx
1992 * leave
1993 * ret
1994 *
1995 * eth_type_trans has 5 byte nop at the beginning. These 5 bytes will be
1996 * replaced with 'call generated_bpf_trampoline'. When it returns
1997 * eth_type_trans will continue executing with original skb and dev pointers.
1998 *
1999 * The assembly code when eth_type_trans is called from trampoline:
2000 *
2001 * push rbp
2002 * mov rbp, rsp
2003 * sub rsp, 24 // space for skb, dev, return value
2004 * push rbx // temp regs to pass start time
2005 * mov qword ptr [rbp - 24], rdi // save skb pointer to stack
2006 * mov qword ptr [rbp - 16], rsi // save dev pointer to stack
2007 * call __bpf_prog_enter // rcu_read_lock and preempt_disable
2008 * mov rbx, rax // remember start time if bpf stats are enabled
2009 * lea rdi, [rbp - 24] // R1==ctx of bpf prog
2010 * call addr_of_jited_FENTRY_prog // bpf prog can access skb and dev
2011 * movabsq rdi, 64bit_addr_of_struct_bpf_prog // unused if bpf stats are off
2012 * mov rsi, rbx // prog start time
2013 * call __bpf_prog_exit // rcu_read_unlock, preempt_enable and stats math
2014 * mov rdi, qword ptr [rbp - 24] // restore skb pointer from stack
2015 * mov rsi, qword ptr [rbp - 16] // restore dev pointer from stack
2016 * call eth_type_trans+5 // execute body of eth_type_trans
2017 * mov qword ptr [rbp - 8], rax // save return value
2018 * call __bpf_prog_enter // rcu_read_lock and preempt_disable
2019 * mov rbx, rax // remember start time in bpf stats are enabled
2020 * lea rdi, [rbp - 24] // R1==ctx of bpf prog
2021 * call addr_of_jited_FEXIT_prog // bpf prog can access skb, dev, return value
2022 * movabsq rdi, 64bit_addr_of_struct_bpf_prog // unused if bpf stats are off
2023 * mov rsi, rbx // prog start time
2024 * call __bpf_prog_exit // rcu_read_unlock, preempt_enable and stats math
2025 * mov rax, qword ptr [rbp - 8] // restore eth_type_trans's return value
2026 * pop rbx
2027 * leave
2028 * add rsp, 8 // skip eth_type_trans's frame
2029 * ret // return to its caller
2030 */
2031 int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *image_end,
2032 const struct btf_func_model *m, u32 flags,
2033 struct bpf_tramp_links *tlinks,
2034 void *orig_call)
2035 {
2036 int ret, i, nr_args = m->nr_args;
2037 int regs_off, ip_off, args_off, stack_size = nr_args * 8, run_ctx_off;
2038 struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY];
2039 struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT];
2040 struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN];
2041 u8 **branches = NULL;
2042 u8 *prog;
2043 bool save_ret;
2044
2045 /* x86-64 supports up to 6 arguments. 7+ can be added in the future */
2046 if (nr_args > 6)
2047 return -ENOTSUPP;
2048
2049 /* Generated trampoline stack layout:
2050 *
2051 * RBP + 8 [ return address ]
2052 * RBP + 0 [ RBP ]
2053 *
2054 * RBP - 8 [ return value ] BPF_TRAMP_F_CALL_ORIG or
2055 * BPF_TRAMP_F_RET_FENTRY_RET flags
2056 *
2057 * [ reg_argN ] always
2058 * [ ... ]
2059 * RBP - regs_off [ reg_arg1 ] program's ctx pointer
2060 *
2061 * RBP - args_off [ args count ] always
2062 *
2063 * RBP - ip_off [ traced function ] BPF_TRAMP_F_IP_ARG flag
2064 *
2065 * RBP - run_ctx_off [ bpf_tramp_run_ctx ]
2066 */
2067
2068 /* room for return value of orig_call or fentry prog */
2069 save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET);
2070 if (save_ret)
2071 stack_size += 8;
2072
2073 regs_off = stack_size;
2074
2075 /* args count */
2076 stack_size += 8;
2077 args_off = stack_size;
2078
2079 if (flags & BPF_TRAMP_F_IP_ARG)
2080 stack_size += 8; /* room for IP address argument */
2081
2082 ip_off = stack_size;
2083
2084 stack_size += (sizeof(struct bpf_tramp_run_ctx) + 7) & ~0x7;
2085 run_ctx_off = stack_size;
2086
2087 if (flags & BPF_TRAMP_F_SKIP_FRAME) {
2088 /* skip patched call instruction and point orig_call to actual
2089 * body of the kernel function.
2090 */
2091 if (is_endbr(*(u32 *)orig_call))
2092 orig_call += ENDBR_INSN_SIZE;
2093 orig_call += X86_PATCH_SIZE;
2094 }
2095
2096 prog = image;
2097
2098 EMIT_ENDBR();
2099 /*
2100 * This is the direct-call trampoline, as such it needs accounting
2101 * for the __fentry__ call.
2102 */
> 2103 x86_call_depth_emit_accounting(&prog, __fentry__);
2104 EMIT1(0x55); /* push rbp */
2105 EMIT3(0x48, 0x89, 0xE5); /* mov rbp, rsp */
2106 EMIT4(0x48, 0x83, 0xEC, stack_size); /* sub rsp, stack_size */
2107 EMIT1(0x53); /* push rbx */
2108
2109 /* Store number of arguments of the traced function:
2110 * mov rax, nr_args
2111 * mov QWORD PTR [rbp - args_off], rax
2112 */
2113 emit_mov_imm64(&prog, BPF_REG_0, 0, (u32) nr_args);
2114 emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -args_off);
2115
2116 if (flags & BPF_TRAMP_F_IP_ARG) {
2117 /* Store IP address of the traced function:
2118 * mov rax, QWORD PTR [rbp + 8]
2119 * sub rax, X86_PATCH_SIZE
2120 * mov QWORD PTR [rbp - ip_off], rax
2121 */
2122 emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, 8);
2123 EMIT4(0x48, 0x83, 0xe8, X86_PATCH_SIZE);
2124 emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -ip_off);
2125 }
2126
2127 save_regs(m, &prog, nr_args, regs_off);
2128
2129 if (flags & BPF_TRAMP_F_CALL_ORIG) {
2130 /* arg1: mov rdi, im */
2131 emit_mov_imm64(&prog, BPF_REG_1, (long) im >> 32, (u32) (long) im);
2132 if (emit_rsb_call(&prog, __bpf_tramp_enter, prog)) {
2133 ret = -EINVAL;
2134 goto cleanup;
2135 }
2136 }
2137
2138 if (fentry->nr_links)
2139 if (invoke_bpf(m, &prog, fentry, regs_off, run_ctx_off,
2140 flags & BPF_TRAMP_F_RET_FENTRY_RET))
2141 return -EINVAL;
2142
2143 if (fmod_ret->nr_links) {
2144 branches = kcalloc(fmod_ret->nr_links, sizeof(u8 *),
2145 GFP_KERNEL);
2146 if (!branches)
2147 return -ENOMEM;
2148
2149 if (invoke_bpf_mod_ret(m, &prog, fmod_ret, regs_off,
2150 run_ctx_off, branches)) {
2151 ret = -EINVAL;
2152 goto cleanup;
2153 }
2154 }
2155
2156 if (flags & BPF_TRAMP_F_CALL_ORIG) {
2157 restore_regs(m, &prog, nr_args, regs_off);
2158
2159 if (flags & BPF_TRAMP_F_ORIG_STACK) {
2160 emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, 8);
2161 EMIT2(0xff, 0xd0); /* call *rax */
2162 } else {
2163 /* call original function */
2164 if (emit_rsb_call(&prog, orig_call, prog)) {
2165 ret = -EINVAL;
2166 goto cleanup;
2167 }
2168 }
2169 /* remember return value in a stack for bpf prog to access */
2170 emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
2171 im->ip_after_call = prog;
2172 memcpy(prog, x86_nops[5], X86_PATCH_SIZE);
2173 prog += X86_PATCH_SIZE;
2174 }
2175
2176 if (fmod_ret->nr_links) {
2177 /* From Intel 64 and IA-32 Architectures Optimization
2178 * Reference Manual, 3.4.1.4 Code Alignment, Assembly/Compiler
2179 * Coding Rule 11: All branch targets should be 16-byte
2180 * aligned.
2181 */
2182 emit_align(&prog, 16);
2183 /* Update the branches saved in invoke_bpf_mod_ret with the
2184 * aligned address of do_fexit.
2185 */
2186 for (i = 0; i < fmod_ret->nr_links; i++)
2187 emit_cond_near_jump(&branches[i], prog, branches[i],
2188 X86_JNE);
2189 }
2190
2191 if (fexit->nr_links)
2192 if (invoke_bpf(m, &prog, fexit, regs_off, run_ctx_off, false)) {
2193 ret = -EINVAL;
2194 goto cleanup;
2195 }
2196
2197 if (flags & BPF_TRAMP_F_RESTORE_REGS)
2198 restore_regs(m, &prog, nr_args, regs_off);
2199
2200 /* This needs to be done regardless. If there were fmod_ret programs,
2201 * the return value is only updated on the stack and still needs to be
2202 * restored to R0.
2203 */
2204 if (flags & BPF_TRAMP_F_CALL_ORIG) {
2205 im->ip_epilogue = prog;
2206 /* arg1: mov rdi, im */
2207 emit_mov_imm64(&prog, BPF_REG_1, (long) im >> 32, (u32) (long) im);
2208 if (emit_rsb_call(&prog, __bpf_tramp_exit, prog)) {
2209 ret = -EINVAL;
2210 goto cleanup;
2211 }
2212 }
2213 /* restore return value of orig_call or fentry prog back into RAX */
2214 if (save_ret)
2215 emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, -8);
2216
2217 EMIT1(0x5B); /* pop rbx */
2218 EMIT1(0xC9); /* leave */
2219 if (flags & BPF_TRAMP_F_SKIP_FRAME)
2220 /* skip our return address and return to parent */
2221 EMIT4(0x48, 0x83, 0xC4, 8); /* add rsp, 8 */
2222 emit_return(&prog, prog);
2223 /* Make sure the trampoline generation logic doesn't overflow */
2224 if (WARN_ON_ONCE(prog > (u8 *)image_end - BPF_INSN_SAFETY)) {
2225 ret = -EFAULT;
2226 goto cleanup;
2227 }
2228 ret = prog - (u8 *)image;
2229
2230 cleanup:
2231 kfree(branches);
2232 return ret;
2233 }
2234

--
0-DAY CI Kernel Test Service
https://01.org/lkp

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