commit b2268d550d20ff860bddfe3a91b1aec00414689a upstream.
The calculation of the distance from %r15 to the caller-allocated portion of the stack frame is copy-pasted into multiple places in the JIT code.
Move it to bpf_jit_prog() and save the result into bpf_jit::frame_off, so that the other parts of the JIT can use it.
Signed-off-by: Ilya Leoshkevich iii@linux.ibm.com Link: https://lore.kernel.org/r/20250624121501.50536-2-iii@linux.ibm.com Signed-off-by: Alexei Starovoitov ast@kernel.org --- arch/s390/net/bpf_jit_comp.c | 56 +++++++++++++++++------------------- 1 file changed, 26 insertions(+), 30 deletions(-)
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index ead8d9ba9032c..12fda05aadf61 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -56,6 +56,7 @@ struct bpf_jit { int prologue_plt; /* Start of prologue hotpatch PLT */ int kern_arena; /* Pool offset of kernel arena address */ u64 user_arena; /* User arena address */ + u32 frame_off; /* Offset of frame from %r15 */ };
#define SEEN_MEM BIT(0) /* use mem[] for temporary storage */ @@ -421,12 +422,9 @@ static void save_regs(struct bpf_jit *jit, u32 rs, u32 re) /* * Restore registers from "rs" (register start) to "re" (register end) on stack */ -static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re, u32 stack_depth) +static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re) { - u32 off = STK_OFF_R6 + (rs - 6) * 8; - - if (jit->seen & SEEN_STACK) - off += STK_OFF + stack_depth; + u32 off = jit->frame_off + STK_OFF_R6 + (rs - 6) * 8;
if (rs == re) /* lg %rs,off(%r15) */ @@ -470,8 +468,7 @@ static int get_end(u16 seen_regs, int start) * Save and restore clobbered registers (6-15) on stack. * We save/restore registers in chunks with gap >= 2 registers. */ -static void save_restore_regs(struct bpf_jit *jit, int op, u32 stack_depth, - u16 extra_regs) +static void save_restore_regs(struct bpf_jit *jit, int op, u16 extra_regs) { u16 seen_regs = jit->seen_regs | extra_regs; const int last = 15, save_restore_size = 6; @@ -494,7 +491,7 @@ static void save_restore_regs(struct bpf_jit *jit, int op, u32 stack_depth, if (op == REGS_SAVE) save_regs(jit, rs, re); else - restore_regs(jit, rs, re, stack_depth); + restore_regs(jit, rs, re); re++; } while (re <= last); } @@ -561,8 +558,7 @@ static void bpf_jit_plt(struct bpf_plt *plt, void *ret, void *target) * Save registers and create stack frame if necessary. * See stack frame layout description in "bpf_jit.h"! */ -static void bpf_jit_prologue(struct bpf_jit *jit, struct bpf_prog *fp, - u32 stack_depth) +static void bpf_jit_prologue(struct bpf_jit *jit, struct bpf_prog *fp) { /* No-op for hotpatching */ /* brcl 0,prologue_plt */ @@ -595,7 +591,7 @@ static void bpf_jit_prologue(struct bpf_jit *jit, struct bpf_prog *fp, jit->seen_regs |= NVREGS; } else { /* Save registers */ - save_restore_regs(jit, REGS_SAVE, stack_depth, + save_restore_regs(jit, REGS_SAVE, fp->aux->exception_boundary ? NVREGS : 0); } /* Setup literal pool */ @@ -617,8 +613,8 @@ static void bpf_jit_prologue(struct bpf_jit *jit, struct bpf_prog *fp, EMIT4(0xb9040000, REG_W1, REG_15); /* la %bfp,STK_160_UNUSED(%r15) (BPF frame pointer) */ EMIT4_DISP(0x41000000, BPF_REG_FP, REG_15, STK_160_UNUSED); - /* aghi %r15,-STK_OFF */ - EMIT4_IMM(0xa70b0000, REG_15, -(STK_OFF + stack_depth)); + /* aghi %r15,-frame_off */ + EMIT4_IMM(0xa70b0000, REG_15, -jit->frame_off); /* stg %w1,152(%r15) (backchain) */ EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, REG_15, 152); @@ -665,13 +661,13 @@ static void call_r1(struct bpf_jit *jit) /* * Function epilogue */ -static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth) +static void bpf_jit_epilogue(struct bpf_jit *jit) { jit->exit_ip = jit->prg; /* Load exit code: lgr %r2,%b0 */ EMIT4(0xb9040000, REG_2, BPF_REG_0); /* Restore registers */ - save_restore_regs(jit, REGS_RESTORE, stack_depth, 0); + save_restore_regs(jit, REGS_RESTORE, 0); if (nospec_uses_trampoline()) { jit->r14_thunk_ip = jit->prg; /* Generate __s390_indirect_jump_r14 thunk */ @@ -862,7 +858,7 @@ static int sign_extend(struct bpf_jit *jit, int r, u8 size, u8 flags) * stack space for the large switch statement. */ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, - int i, bool extra_pass, u32 stack_depth) + int i, bool extra_pass) { struct bpf_insn *insn = &fp->insnsi[i]; s32 branch_oc_off = insn->off; @@ -1783,9 +1779,9 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, * Note 2: We assume that the verifier does not let us call the * main program, which clears the tail call counter on entry. */ - /* mvc STK_OFF_TCCNT(4,%r15),N(%r15) */ + /* mvc STK_OFF_TCCNT(4,%r15),frame_off+STK_OFF_TCCNT(%r15) */ _EMIT6(0xd203f000 | STK_OFF_TCCNT, - 0xf000 | (STK_OFF_TCCNT + STK_OFF + stack_depth)); + 0xf000 | (jit->frame_off + STK_OFF_TCCNT));
/* Sign-extend the kfunc arguments. */ if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) { @@ -1836,10 +1832,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, * goto out; */
- if (jit->seen & SEEN_STACK) - off = STK_OFF_TCCNT + STK_OFF + stack_depth; - else - off = STK_OFF_TCCNT; + off = jit->frame_off + STK_OFF_TCCNT; /* lhi %w0,1 */ EMIT4_IMM(0xa7080000, REG_W0, 1); /* laal %w1,%w0,off(%r15) */ @@ -1869,7 +1862,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, /* * Restore registers before calling function */ - save_restore_regs(jit, REGS_RESTORE, stack_depth, 0); + save_restore_regs(jit, REGS_RESTORE, 0);
/* * goto *(prog->bpf_func + tail_call_start); @@ -2161,7 +2154,7 @@ static int bpf_set_addr(struct bpf_jit *jit, int i) * Compile eBPF program into s390x code */ static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp, - bool extra_pass, u32 stack_depth) + bool extra_pass) { int i, insn_count, lit32_size, lit64_size; u64 kern_arena; @@ -2170,24 +2163,28 @@ static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp, jit->lit64 = jit->lit64_start; jit->prg = 0; jit->excnt = 0; + if (is_first_pass(jit) || (jit->seen & SEEN_STACK)) + jit->frame_off = STK_OFF + round_up(fp->aux->stack_depth, 8); + else + jit->frame_off = 0;
kern_arena = bpf_arena_get_kern_vm_start(fp->aux->arena); if (kern_arena) jit->kern_arena = _EMIT_CONST_U64(kern_arena); jit->user_arena = bpf_arena_get_user_vm_start(fp->aux->arena);
- bpf_jit_prologue(jit, fp, stack_depth); + bpf_jit_prologue(jit, fp); if (bpf_set_addr(jit, 0) < 0) return -1; for (i = 0; i < fp->len; i += insn_count) { - insn_count = bpf_jit_insn(jit, fp, i, extra_pass, stack_depth); + insn_count = bpf_jit_insn(jit, fp, i, extra_pass); if (insn_count < 0) return -1; /* Next instruction address */ if (bpf_set_addr(jit, i + insn_count) < 0) return -1; } - bpf_jit_epilogue(jit, stack_depth); + bpf_jit_epilogue(jit);
lit32_size = jit->lit32 - jit->lit32_start; lit64_size = jit->lit64 - jit->lit64_start; @@ -2263,7 +2260,6 @@ static struct bpf_binary_header *bpf_jit_alloc(struct bpf_jit *jit, */ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) { - u32 stack_depth = round_up(fp->aux->stack_depth, 8); struct bpf_prog *tmp, *orig_fp = fp; struct bpf_binary_header *header; struct s390_jit_data *jit_data; @@ -2316,7 +2312,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) * - 3: Calculate program size and addrs array */ for (pass = 1; pass <= 3; pass++) { - if (bpf_jit_prog(&jit, fp, extra_pass, stack_depth)) { + if (bpf_jit_prog(&jit, fp, extra_pass)) { fp = orig_fp; goto free_addrs; } @@ -2330,7 +2326,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) goto free_addrs; } skip_init_ctx: - if (bpf_jit_prog(&jit, fp, extra_pass, stack_depth)) { + if (bpf_jit_prog(&jit, fp, extra_pass)) { bpf_jit_binary_free(header); fp = orig_fp; goto free_addrs;