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ARC, bpf: Fix issues reported by the static analyzers

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Also updated couple of comments along the way.

One of the issues reported was indeed a bug in the code:

  memset(ctx, 0, sizeof(ctx))      // original line
  memset(ctx, 0, sizeof(*ctx))     // fixed line

That was a nice catch.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202405222314.UG5F2NHn-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202405232036.Xqoc3b0J-lkp@intel.com/
Signed-off-by: Shahab Vahedi <shahab@synopsys.com>
Link: https://lore.kernel.org/r/20240525035628.1026-1-list+bpf@vahedi.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Shahab Vahedi 2024-05-25 05:56:28 +02:00 committed by Alexei Starovoitov
parent 590016ad83
commit dd6a403795
3 changed files with 18 additions and 16 deletions
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2
arch/arc/net/bpf_jit.h
View File

@ -39,7 +39,7 @@
/************** Functions that the back-end must provide **************/ /************** Functions that the back-end must provide **************/
/* Extension for 32-bit operations. */ /* Extension for 32-bit operations. */
inline u8 zext(u8 *buf, u8 rd); u8 zext(u8 *buf, u8 rd);
/***** Moves *****/ /***** Moves *****/
u8 mov_r32(u8 *buf, u8 rd, u8 rs, u8 sign_ext); u8 mov_r32(u8 *buf, u8 rd, u8 rs, u8 sign_ext);
u8 mov_r32_i32(u8 *buf, u8 reg, s32 imm); u8 mov_r32_i32(u8 *buf, u8 reg, s32 imm);

10
arch/arc/net/bpf_jit_arcv2.c
View File

@ -62,7 +62,7 @@ enum {
* If/when we decide to add ARCv2 instructions that do use register pairs, * If/when we decide to add ARCv2 instructions that do use register pairs,
* the mapping, hopefully, doesn't need to be revisited. * the mapping, hopefully, doesn't need to be revisited.
*/ */
const u8 bpf2arc[][2] = { static const u8 bpf2arc[][2] = {
/* Return value from in-kernel function, and exit value from eBPF */ /* Return value from in-kernel function, and exit value from eBPF */
[BPF_REG_0] = {ARC_R_8, ARC_R_9}, [BPF_REG_0] = {ARC_R_8, ARC_R_9},
/* Arguments from eBPF program to in-kernel function */ /* Arguments from eBPF program to in-kernel function */
@ -1302,7 +1302,7 @@ static u8 arc_b(u8 *buf, s32 offset)
/************* Packers (Deal with BPF_REGs) **************/ /************* Packers (Deal with BPF_REGs) **************/
inline u8 zext(u8 *buf, u8 rd) u8 zext(u8 *buf, u8 rd)
{ {
if (rd != BPF_REG_FP) if (rd != BPF_REG_FP)
return arc_movi_r(buf, REG_HI(rd), 0); return arc_movi_r(buf, REG_HI(rd), 0);
@ -2235,6 +2235,7 @@ u8 gen_swap(u8 *buf, u8 rd, u8 size, u8 endian, bool force, bool do_zext)
break; break;
default: default:
/* The caller must have handled this. */ /* The caller must have handled this. */
break;
} }
} else { } else {
/* /*
@ -2253,6 +2254,7 @@ u8 gen_swap(u8 *buf, u8 rd, u8 size, u8 endian, bool force, bool do_zext)
break; break;
default: default:
/* The caller must have handled this. */ /* The caller must have handled this. */
break;
} }
} }
@ -2517,7 +2519,7 @@ u8 arc_epilogue(u8 *buf, u32 usage, u16 frame_size)
#define JCC64_NR_OF_JMPS 3 /* Number of jumps in jcc64 template. */ #define JCC64_NR_OF_JMPS 3 /* Number of jumps in jcc64 template. */
#define JCC64_INSNS_TO_END 3 /* Number of insn. inclusive the 2nd jmp to end. */ #define JCC64_INSNS_TO_END 3 /* Number of insn. inclusive the 2nd jmp to end. */
#define JCC64_SKIP_JMP 1 /* Index of the "skip" jump to "end". */ #define JCC64_SKIP_JMP 1 /* Index of the "skip" jump to "end". */
const struct { static const struct {
/* /*
* "jit_off" is common between all "jmp[]" and is coupled with * "jit_off" is common between all "jmp[]" and is coupled with
* "cond" of each "jmp[]" instance. e.g.: * "cond" of each "jmp[]" instance. e.g.:
@ -2883,7 +2885,7 @@ u8 gen_jmp_64(u8 *buf, u8 rd, u8 rs, u8 cond, u32 curr_off, u32 targ_off)
* The "ARC_CC_SET" becomes "CC_unequal" because of the "tst" * The "ARC_CC_SET" becomes "CC_unequal" because of the "tst"
* instruction that precedes the conditional branch. * instruction that precedes the conditional branch.
*/ */
const u8 arcv2_32_jmps[ARC_CC_LAST] = { static const u8 arcv2_32_jmps[ARC_CC_LAST] = {
[ARC_CC_UGT] = CC_great_u, [ARC_CC_UGT] = CC_great_u,
[ARC_CC_UGE] = CC_great_eq_u, [ARC_CC_UGE] = CC_great_eq_u,
[ARC_CC_ULT] = CC_less_u, [ARC_CC_ULT] = CC_less_u,

22
arch/arc/net/bpf_jit_core.c
View File

@ -159,7 +159,7 @@ static void jit_dump(const struct jit_context *ctx)
/* Initialise the context so there's no garbage. */ /* Initialise the context so there's no garbage. */
static int jit_ctx_init(struct jit_context *ctx, struct bpf_prog *prog) static int jit_ctx_init(struct jit_context *ctx, struct bpf_prog *prog)
{ {
memset(ctx, 0, sizeof(ctx)); memset(ctx, 0, sizeof(*ctx));
ctx->orig_prog = prog; ctx->orig_prog = prog;
@ -167,7 +167,7 @@ static int jit_ctx_init(struct jit_context *ctx, struct bpf_prog *prog)
ctx->prog = bpf_jit_blind_constants(prog); ctx->prog = bpf_jit_blind_constants(prog);
if (IS_ERR(ctx->prog)) if (IS_ERR(ctx->prog))
return PTR_ERR(ctx->prog); return PTR_ERR(ctx->prog);
ctx->blinded = (ctx->prog == ctx->orig_prog ? false : true); ctx->blinded = (ctx->prog != ctx->orig_prog);
/* If the verifier doesn't zero-extend, then we have to do it. */ /* If the verifier doesn't zero-extend, then we have to do it. */
ctx->do_zext = !ctx->prog->aux->verifier_zext; ctx->do_zext = !ctx->prog->aux->verifier_zext;
@ -1182,12 +1182,12 @@ static int jit_prepare(struct jit_context *ctx)
} }
/* /*
* All the "handle_*()" functions have been called before by the * jit_compile() is the real compilation phase. jit_prepare() is
* "jit_prepare()". If there was an error, we would know by now. * invoked before jit_compile() as a dry-run to make sure everything
* Therefore, no extra error checking at this point, other than * will go OK and allocate the necessary memory.
* a sanity check at the end that expects the calculated length *
* (jit.len) to be equal to the length of generated instructions * In the end, jit_compile() checks if it has produced the same number
* (jit.index). * of instructions as jit_prepare() would.
*/ */
static int jit_compile(struct jit_context *ctx) static int jit_compile(struct jit_context *ctx)
{ {
@ -1407,9 +1407,9 @@ static struct bpf_prog *do_extra_pass(struct bpf_prog *prog)
/* /*
* This function may be invoked twice for the same stream of BPF * This function may be invoked twice for the same stream of BPF
* instructions. The "extra pass" happens, when there are "call"s * instructions. The "extra pass" happens, when there are
* involved that their addresses are not known during the first * (re)locations involved that their addresses are not known
* invocation. * during the first run.
*/ */
struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
{ {