wireguard-linux/arch/riscv/kernel/vdso/Makefile, branch jd/orphan-parallel

kbuild: explicitly specify the build id style

2020-10-09T14:57:30Z

ld's --build-id defaults to "sha1" style, while lld defaults to "fast". The build IDs are very different between the two, which may confuse programs that reference them. Signed-off-by: Bill Wendling Acked-by: David S. Miller Signed-off-by: Masahiro Yamada

riscv: disable stack-protector for vDSO

2020-08-04T22:02:49Z

Currently, building the vDSO with clang leads assembler errors like the following: /tmp/vgettimeofday-1ae0d2.s: Assembler messages: /tmp/vgettimeofday-1ae0d2.s:28: Error: bad expression /tmp/vgettimeofday-1ae0d2.s:28: Error: illegal operands `auipc a2,%got_pcrel_hi(__stack_chk_guard)' Disable the stack-protector for vDSO to fix these. Link: https://github.com/ClangBuiltLinux/linux/issues/1112 Signed-off-by: Tobias Klauser Signed-off-by: Palmer Dabbelt

riscv: Allow building with kcov coverage

2020-07-30T18:37:35Z

Add ARCH_HAS_KCOV and HAVE_GCC_PLUGINS to the riscv Kconfig. Also disable instrumentation of some early boot code and vdso. Boot-tested on QEMU's riscv64 virt machine. Signed-off-by: Tobias Klauser Acked-by: Dmitry Vyukov Signed-off-by: Palmer Dabbelt

riscv: Fixup __vdso_gettimeofday broke dynamic ftrace

2020-06-25T22:38:39Z

For linux-5.8-rc1, enable ftrace of riscv will cause boot panic: [ 2.388980] Run /sbin/init as init process [ 2.529938] init[39]: unhandled signal 4 code 0x1 at 0x0000003ff449e000 [ 2.531078] CPU: 0 PID: 39 Comm: init Not tainted 5.8.0-rc1-dirty #13 [ 2.532719] epc: 0000003ff449e000 ra : 0000003ff449e954 sp : 0000003fffedb900 [ 2.534005] gp : 00000000000e8528 tp : 0000003ff449d800 t0 : 000000000000001e [ 2.534965] t1 : 000000000000000a t2 : 0000003fffedb89e s0 : 0000003fffedb920 [ 2.536279] s1 : 0000003fffedb940 a0 : 0000003ff43d4b2c a1 : 0000000000000000 [ 2.537334] a2 : 0000000000000001 a3 : 0000000000000000 a4 : fffffffffbad8000 [ 2.538466] a5 : 0000003ff449e93a a6 : 0000000000000000 a7 : 0000000000000000 [ 2.539511] s2 : 0000000000000000 s3 : 0000003ff448412c s4 : 0000000000000010 [ 2.541260] s5 : 0000000000000016 s6 : 00000000000d0a30 s7 : 0000003fffedba70 [ 2.542152] s8 : 0000000000000000 s9 : 0000000000000000 s10: 0000003fffedb960 [ 2.543335] s11: 0000000000000000 t3 : 0000000000000000 t4 : 0000003fffedb8a0 [ 2.544471] t5 : 0000000000000000 t6 : 0000000000000000 [ 2.545730] status: 0000000000004020 badaddr: 00000000464c457f cause: 0000000000000002 [ 2.549867] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000004 [ 2.551267] CPU: 0 PID: 1 Comm: init Not tainted 5.8.0-rc1-dirty #13 [ 2.552061] Call Trace: [ 2.552626] [] walk_stackframe+0x0/0xc4 [ 2.553486] [] show_stack+0x40/0x4c [ 2.553995] [] dump_stack+0x7a/0x98 [ 2.554615] [] panic+0x114/0x2f4 [ 2.555395] [] do_exit+0x89c/0x8c2 [ 2.555949] [] do_group_exit+0x3a/0x90 [ 2.556715] [] get_signal+0xe2/0x6e6 [ 2.557388] [] do_notify_resume+0x6a/0x37a [ 2.558089] [] ret_from_exception+0x0/0xc "ra:0x3ff449e954" is the return address of "call _mcount" in the prologue of __vdso_gettimeofday(). Without proper relocate, pc jmp to 0x0000003ff449e000 (vdso map base) with a illegal instruction trap. The solution comes from arch/arm64/kernel/vdso/Makefile: CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) - CC_FLAGS_SCS is ShadowCallStack feature in Clang and only implemented for arm64, no use for riscv. Fixes: ad5d1122b82f ("riscv: use vDSO common flow to reduce the latency of the time-related functions") Cc: stable@vger.kernel.org Signed-off-by: Guo Ren Reviewed-by: Vincent Chen Signed-off-by: Palmer Dabbelt

riscv: Add -fPIC option to CFLAGS_vgettimeofday.o

2020-06-25T21:58:59Z

The time related vDSO functions use a variable, vdso_data, to access the vDSO data page to get the system time information. Because the vdso_data for CFLAGS_vgettimeofday.o is an external variable defined in vdso.o, the CFLAGS_vgettimeofday.o should be compiled with -fPIC to ensure that vdso_data is addressable. Reported-by: kernel test robot Signed-off-by: Vincent Chen Signed-off-by: Palmer Dabbelt

riscv: use vDSO common flow to reduce the latency of the time-related functions

2020-06-11T02:47:16Z

Even if RISC-V has supported the vDSO feature, the latency of the functions for obtaining the system time is still expensive. It is because these functions still trigger a corresponding system call in the process, which slows down the response time. If we want to remove the system call to reduce the latency, the kernel should have the ability to output the system clock information to userspace. This patch introduces the vDSO common flow to enable the kernel to achieve the above feature and uses "rdtime" instruction to obtain the current time in the user space. Under this condition, the latency cost by the ecall from U-mode to S-mode can be eliminated. After applying this patch, the latency of gettimeofday() measured on the HiFive unleashed board can be reduced by %61. Signed-off-by: Vincent Chen Reviewed-by: Atish Patra Signed-off-by: Palmer Dabbelt

riscv: add Linux note to vdso

2020-05-04T21:22:34Z

The Linux note in the vdso allows glibc to check the running kernel version without having to issue the uname syscall. Signed-off-by: Andreas Schwab Signed-off-by: Palmer Dabbelt

riscv: fix vdso build with lld

2020-04-21T22:22:45Z

When building with the LLVM linker this error occurrs: LD arch/riscv/kernel/vdso/vdso-syms.o ld.lld: error: no input files This happens because the lld treats -R as an alias to -rpath, as opposed to ld where -R means --just-symbols. Use the long option name for compatibility between the two. Link: https://github.com/ClangBuiltLinux/linux/issues/805 Reported-by: Dmitry Golovin Reviewed-by: Nick Desaulniers Signed-off-by: Ilie Halip Reviewed-by: Fangrui Song Signed-off-by: Palmer Dabbelt

riscv: delete temporary files

2020-01-18T21:22:13Z

Temporary files used in the VDSO build process linger on even after make mrproper: vdso-dummy.o.tmp, vdso.so.dbg.tmp. Delete them once they're no longer needed. Signed-off-by: Ilie Halip Signed-off-by: Paul Walmsley

riscv: Fix perf record without libelf support

2019-07-31T19:26:10Z

This patch fix following perf record error by linking vdso.so with build id. perf.data perf.data.old [ perf record: Woken up 1 times to write data ] free(): double free detected in tcache 2 Aborted perf record use filename__read_build_id(util/symbol-minimal.c) to get build id when libelf is not supported. When vdso.so is linked without build id, the section size of PT_NOTE will be zero, buf size will realloc to zero and cause memory corruption. Signed-off-by: Mao Han Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Signed-off-by: Paul Walmsley