| Message ID | 20191206080741.12306-1-alobakin@dlink.ru |
|---|---|
| State | Not Applicable |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [mips-fixes] MIPS: BPF: eBPF JIT: check for MIPS ISA compliance in Kconfig | expand |
Hello, Alexander Lobakin wrote: > It is completely wrong to check for compile-time MIPS ISA revision in > the body of bpf_int_jit_compile() as it may lead to get MIPS JIT fully > omitted by the CC while the rest system will think that the JIT is > actually present and works [1]. > We can check if the selected CPU really supports MIPS eBPF JIT at > configure time and avoid such situations when kernel can be built > without both JIT and interpreter, but with CONFIG_BPF_SYSCALL=y. > > [1] https://lore.kernel.org/linux-mips/09d713a59665d745e21d021deeaebe0a@dlink.ru/ Applied to mips-fixes. > commit 3721376d7d02 > https://git.kernel.org/mips/c/3721376d7d02 > > Fixes: 716850ab104d ("MIPS: eBPF: Initial eBPF support for MIPS32 architecture.") > Signed-off-by: Alexander Lobakin <alobakin@dlink.ru> > Signed-off-by: Paul Burton <paulburton@kernel.org> Thanks, Paul [ This message was auto-generated; if you believe anything is incorrect then please email paulburton@kernel.org to report it. ]
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index add388236f4e..407b85ee93e4 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -47,7 +47,7 @@ config MIPS select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE if CPU_SUPPORTS_HUGEPAGES select HAVE_ASM_MODVERSIONS - select HAVE_EBPF_JIT if (!CPU_MICROMIPS) + select HAVE_EBPF_JIT if !CPU_MICROMIPS && TARGET_ISA_REV >= 2 select HAVE_CONTEXT_TRACKING select HAVE_COPY_THREAD_TLS select HAVE_C_RECORDMCOUNT diff --git a/arch/mips/net/ebpf_jit.c b/arch/mips/net/ebpf_jit.c index 46b76751f3a5..a2405d5f7d1e 100644 --- a/arch/mips/net/ebpf_jit.c +++ b/arch/mips/net/ebpf_jit.c @@ -1803,7 +1803,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) unsigned int image_size; u8 *image_ptr; - if (!prog->jit_requested || MIPS_ISA_REV < 2) + if (!prog->jit_requested) return prog; tmp = bpf_jit_blind_constants(prog);
It is completely wrong to check for compile-time MIPS ISA revision in the body of bpf_int_jit_compile() as it may lead to get MIPS JIT fully omitted by the CC while the rest system will think that the JIT is actually present and works [1]. We can check if the selected CPU really supports MIPS eBPF JIT at configure time and avoid such situations when kernel can be built without both JIT and interpreter, but with CONFIG_BPF_SYSCALL=y. [1] https://lore.kernel.org/linux-mips/09d713a59665d745e21d021deeaebe0a@dlink.ru/ Fixes: 716850ab104d ("MIPS: eBPF: Initial eBPF support for MIPS32 architecture.") Cc: <stable@vger.kernel.org> # v5.2+ Signed-off-by: Alexander Lobakin <alobakin@dlink.ru> --- arch/mips/Kconfig | 2 +- arch/mips/net/ebpf_jit.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)