lkml.org 
[lkml]   [2014]   [May]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: mmotm 2014-05-09-16-17 uploaded (ptrace-ab.hi vs. net/core/filter.c)
From
On Tue, May 13, 2014 at 10:14 AM, David Miller <davem@davemloft.net> wrote:
> From: Randy Dunlap <rdunlap@infradead.org>
> Date: Sat, 10 May 2014 10:15:37 -0700
>
>> On 05/09/2014 04:18 PM, akpm@linux-foundation.org wrote:
>>> The mm-of-the-moment snapshot 2014-05-09-16-17 has been uploaded to
>>>
>>> http://www.ozlabs.org/~akpm/mmotm/
>>>
>>
>>
>> uml defconfig on x86_64: (also happens in linux-next)
>>
>> net/core/filter.c:57:0: warning: "R8" redefined [enabled by default]
>> arch/x86/include/uapi/asm/ptrace-abi.h:38:0: note: this is the location of the previous definition
>>
>> Same warnings for R9 and R10.
>
> I'm going to commit the following to net-next to fix this,
> thanks Randy.
>
> ====================
> [PATCH] net: filter: Fix redefinition warnings on x86-64.
>
> Do not collide with the x86-64 PTRACE user API namespace.
>
> net/core/filter.c:57:0: warning: "R8" redefined [enabled by default]
> arch/x86/include/uapi/asm/ptrace-abi.h:38:0: note: this is the location of the previous definition
>
> Fix by adding a BPF_ prefix to the register macros.
>
> Reported-by: Randy Dunlap <rdunlap@infradead.org>
> Signed-off-by: David S. Miller <davem@davemloft.net>

thank you for taking care of it.
Next time will remember to do arch=um build...

Acked-by: Alexei Starovoitov <ast@plumgrid.com>

> ---
> net/core/filter.c | 71 +++++++++++++++++++++++++++++--------------------------
> 1 file changed, 37 insertions(+), 34 deletions(-)
>
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 9aaa05a..c442a0d 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -46,17 +46,17 @@
> #include <linux/if_vlan.h>
>
> /* Registers */
> -#define R0 regs[BPF_REG_0]
> -#define R1 regs[BPF_REG_1]
> -#define R2 regs[BPF_REG_2]
> -#define R3 regs[BPF_REG_3]
> -#define R4 regs[BPF_REG_4]
> -#define R5 regs[BPF_REG_5]
> -#define R6 regs[BPF_REG_6]
> -#define R7 regs[BPF_REG_7]
> -#define R8 regs[BPF_REG_8]
> -#define R9 regs[BPF_REG_9]
> -#define R10 regs[BPF_REG_10]
> +#define BPF_R0 regs[BPF_REG_0]
> +#define BPF_R1 regs[BPF_REG_1]
> +#define BPF_R2 regs[BPF_REG_2]
> +#define BPF_R3 regs[BPF_REG_3]
> +#define BPF_R4 regs[BPF_REG_4]
> +#define BPF_R5 regs[BPF_REG_5]
> +#define BPF_R6 regs[BPF_REG_6]
> +#define BPF_R7 regs[BPF_REG_7]
> +#define BPF_R8 regs[BPF_REG_8]
> +#define BPF_R9 regs[BPF_REG_9]
> +#define BPF_R10 regs[BPF_REG_10]
>
> /* Named registers */
> #define A regs[insn->a_reg]
> @@ -383,10 +383,12 @@ select_insn:
>
> /* CALL */
> JMP_CALL_0:
> - /* Function call scratches R1-R5 registers, preserves R6-R9,
> - * and stores return value into R0.
> + /* Function call scratches BPF_R1-BPF_R5 registers,
> + * preserves BPF_R6-BPF_R9, and stores return value
> + * into BPF_R0.
> */
> - R0 = (__bpf_call_base + insn->imm)(R1, R2, R3, R4, R5);
> + BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
> + BPF_R4, BPF_R5);
> CONT;
>
> /* JMP */
> @@ -478,7 +480,7 @@ select_insn:
> }
> CONT;
> JMP_EXIT_0:
> - return R0;
> + return BPF_R0;
>
> /* STX and ST and LDX*/
> #define LDST(SIZEOP, SIZE) \
> @@ -505,18 +507,19 @@ select_insn:
> atomic64_add((u64) X, (atomic64_t *)(unsigned long)
> (A + insn->off));
> CONT;
> - LD_ABS_W: /* R0 = ntohl(*(u32 *) (skb->data + K)) */
> + LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + K)) */
> off = K;
> load_word:
> - /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are only
> - * appearing in the programs where ctx == skb. All programs
> - * keep 'ctx' in regs[BPF_REG_CTX] == R6, sk_convert_filter()
> - * saves it in R6, internal BPF verifier will check that
> - * R6 == ctx.
> + /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
> + * only appearing in the programs where ctx ==
> + * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
> + * == BPF_R6, sk_convert_filter() saves it in BPF_R6,
> + * internal BPF verifier will check that BPF_R6 ==
> + * ctx.
> *
> - * BPF_ABS and BPF_IND are wrappers of function calls, so
> - * they scratch R1-R5 registers, preserve R6-R9, and store
> - * return value into R0.
> + * BPF_ABS and BPF_IND are wrappers of function calls,
> + * so they scratch BPF_R1-BPF_R5 registers, preserve
> + * BPF_R6-BPF_R9, and store return value into BPF_R0.
> *
> * Implicit input:
> * ctx
> @@ -526,39 +529,39 @@ load_word:
> * K == 32-bit immediate
> *
> * Output:
> - * R0 - 8/16/32-bit skb data converted to cpu endianness
> + * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
> */
> ptr = load_pointer((struct sk_buff *) ctx, off, 4, &tmp);
> if (likely(ptr != NULL)) {
> - R0 = get_unaligned_be32(ptr);
> + BPF_R0 = get_unaligned_be32(ptr);
> CONT;
> }
> return 0;
> - LD_ABS_H: /* R0 = ntohs(*(u16 *) (skb->data + K)) */
> + LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + K)) */
> off = K;
> load_half:
> ptr = load_pointer((struct sk_buff *) ctx, off, 2, &tmp);
> if (likely(ptr != NULL)) {
> - R0 = get_unaligned_be16(ptr);
> + BPF_R0 = get_unaligned_be16(ptr);
> CONT;
> }
> return 0;
> - LD_ABS_B: /* R0 = *(u8 *) (ctx + K) */
> + LD_ABS_B: /* BPF_R0 = *(u8 *) (ctx + K) */
> off = K;
> load_byte:
> ptr = load_pointer((struct sk_buff *) ctx, off, 1, &tmp);
> if (likely(ptr != NULL)) {
> - R0 = *(u8 *)ptr;
> + BPF_R0 = *(u8 *)ptr;
> CONT;
> }
> return 0;
> - LD_IND_W: /* R0 = ntohl(*(u32 *) (skb->data + X + K)) */
> + LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + X + K)) */
> off = K + X;
> goto load_word;
> - LD_IND_H: /* R0 = ntohs(*(u16 *) (skb->data + X + K)) */
> + LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + X + K)) */
> off = K + X;
> goto load_half;
> - LD_IND_B: /* R0 = *(u8 *) (skb->data + X + K) */
> + LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + X + K) */
> off = K + X;
> goto load_byte;
>
> @@ -1001,7 +1004,7 @@ do_pass:
> *insn = BPF_ALU64_REG(BPF_MOV, BPF_REG_TMP, BPF_REG_A);
> insn++;
>
> - /* A = R0 = *(u8 *) (skb->data + K) */
> + /* A = BPF_R0 = *(u8 *) (skb->data + K) */
> *insn = BPF_LD_ABS(BPF_B, fp->k);
> insn++;
>
> --
> 1.9.0
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/


\
 
 \ /
  Last update: 2014-05-13 20:21    [W:0.076 / U:0.524 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site