diff options
Diffstat (limited to 'target/linux/generic/backport-5.10/050-v5.16-04-mips-bpf-Add-JIT-workarounds-for-CPU-errata.patch')
| -rw-r--r-- | target/linux/generic/backport-5.10/050-v5.16-04-mips-bpf-Add-JIT-workarounds-for-CPU-errata.patch | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.10/050-v5.16-04-mips-bpf-Add-JIT-workarounds-for-CPU-errata.patch b/target/linux/generic/backport-5.10/050-v5.16-04-mips-bpf-Add-JIT-workarounds-for-CPU-errata.patch new file mode 100644 index 0000000000..63553ebe58 --- /dev/null +++ b/target/linux/generic/backport-5.10/050-v5.16-04-mips-bpf-Add-JIT-workarounds-for-CPU-errata.patch @@ -0,0 +1,120 @@ +From: Johan Almbladh <johan.almbladh@anyfinetworks.com> +Date: Tue, 5 Oct 2021 18:54:06 +0200 +Subject: [PATCH] mips: bpf: Add JIT workarounds for CPU errata + +This patch adds workarounds for the following CPU errata to the MIPS +eBPF JIT, if enabled in the kernel configuration. + + - R10000 ll/sc weak ordering + - Loongson-3 ll/sc weak ordering + - Loongson-2F jump hang + +The Loongson-2F nop errata is implemented in uasm, which the JIT uses, +so no additional mitigations are needed for that. + +Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> +Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com> +--- + +--- a/arch/mips/net/bpf_jit_comp.c ++++ b/arch/mips/net/bpf_jit_comp.c +@@ -404,6 +404,7 @@ void emit_alu_r(struct jit_context *ctx, + /* Atomic read-modify-write (32-bit) */ + void emit_atomic_r(struct jit_context *ctx, u8 dst, u8 src, s16 off, u8 code) + { ++ LLSC_sync(ctx); + emit(ctx, ll, MIPS_R_T9, off, dst); + switch (code) { + case BPF_ADD: +@@ -420,18 +421,19 @@ void emit_atomic_r(struct jit_context *c + break; + } + emit(ctx, sc, MIPS_R_T8, off, dst); +- emit(ctx, beqz, MIPS_R_T8, -16); ++ emit(ctx, LLSC_beqz, MIPS_R_T8, -16 - LLSC_offset); + emit(ctx, nop); /* Delay slot */ + } + + /* Atomic compare-and-exchange (32-bit) */ + void emit_cmpxchg_r(struct jit_context *ctx, u8 dst, u8 src, u8 res, s16 off) + { ++ LLSC_sync(ctx); + emit(ctx, ll, MIPS_R_T9, off, dst); + emit(ctx, bne, MIPS_R_T9, res, 12); + emit(ctx, move, MIPS_R_T8, src); /* Delay slot */ + emit(ctx, sc, MIPS_R_T8, off, dst); +- emit(ctx, beqz, MIPS_R_T8, -20); ++ emit(ctx, LLSC_beqz, MIPS_R_T8, -20 - LLSC_offset); + emit(ctx, move, res, MIPS_R_T9); /* Delay slot */ + clobber_reg(ctx, res); + } +--- a/arch/mips/net/bpf_jit_comp.h ++++ b/arch/mips/net/bpf_jit_comp.h +@@ -87,7 +87,7 @@ struct jit_context { + }; + + /* Emit the instruction if the JIT memory space has been allocated */ +-#define emit(ctx, func, ...) \ ++#define __emit(ctx, func, ...) \ + do { \ + if ((ctx)->target != NULL) { \ + u32 *p = &(ctx)->target[ctx->jit_index]; \ +@@ -95,6 +95,30 @@ do { \ + } \ + (ctx)->jit_index++; \ + } while (0) ++#define emit(...) __emit(__VA_ARGS__) ++ ++/* Workaround for R10000 ll/sc errata */ ++#ifdef CONFIG_WAR_R10000 ++#define LLSC_beqz beqzl ++#else ++#define LLSC_beqz beqz ++#endif ++ ++/* Workaround for Loongson-3 ll/sc errata */ ++#ifdef CONFIG_CPU_LOONGSON3_WORKAROUNDS ++#define LLSC_sync(ctx) emit(ctx, sync, 0) ++#define LLSC_offset 4 ++#else ++#define LLSC_sync(ctx) ++#define LLSC_offset 0 ++#endif ++ ++/* Workaround for Loongson-2F jump errata */ ++#ifdef CONFIG_CPU_JUMP_WORKAROUNDS ++#define JALR_MASK 0xffffffffcfffffffULL ++#else ++#define JALR_MASK (~0ULL) ++#endif + + /* + * Mark a BPF register as accessed, it needs to be +--- a/arch/mips/net/bpf_jit_comp64.c ++++ b/arch/mips/net/bpf_jit_comp64.c +@@ -375,6 +375,7 @@ static void emit_atomic_r64(struct jit_c + u8 t1 = MIPS_R_T6; + u8 t2 = MIPS_R_T7; + ++ LLSC_sync(ctx); + emit(ctx, lld, t1, off, dst); + switch (code) { + case BPF_ADD: +@@ -391,7 +392,7 @@ static void emit_atomic_r64(struct jit_c + break; + } + emit(ctx, scd, t2, off, dst); +- emit(ctx, beqz, t2, -16); ++ emit(ctx, LLSC_beqz, t2, -16 - LLSC_offset); + emit(ctx, nop); /* Delay slot */ + } + +@@ -414,7 +415,7 @@ static int emit_call(struct jit_context + push_regs(ctx, ctx->clobbered & JIT_CALLER_REGS, 0, 0); + + /* Emit function call */ +- emit_mov_i64(ctx, tmp, addr); ++ emit_mov_i64(ctx, tmp, addr & JALR_MASK); + emit(ctx, jalr, MIPS_R_RA, tmp); + emit(ctx, nop); /* Delay slot */ + |