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net: filter: Fix some minor issues in sparc JIT.

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Correct conventions comments.  %o4 and %o5 were swapped,
%g3 was not documented.

Use r_TMP instead of r_SKB_DATA + r_OFF where possible in
assembler stubs.

Correct discussion of %o4 and %o5 in one of bpf_jit_compile()'s
comments.

Based upon feedback from Richard Mortimer.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2012-04-17 16:08:29 -04:00
parent b3d7b2f2f0
commit 7b56f76edf
3 changed files with 6 additions and 5 deletions
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5
arch/sparc/net/bpf_jit.h
View File

@ -4,13 +4,14 @@
/* Conventions: /* Conventions:
* %g1 : temporary * %g1 : temporary
* %g2 : Secondary temporary used by SKB data helper stubs. * %g2 : Secondary temporary used by SKB data helper stubs.
* %g3 : packet offset passed into SKB data helper stubs.
* %o0 : pointer to skb (first argument given to JIT function) * %o0 : pointer to skb (first argument given to JIT function)
* %o1 : BPF A accumulator * %o1 : BPF A accumulator
* %o2 : BPF X accumulator * %o2 : BPF X accumulator
* %o3 : Holds saved %o7 so we can call helper functions without needing * %o3 : Holds saved %o7 so we can call helper functions without needing
* to allocate a register window. * to allocate a register window.
* %o4 : skb->data * %o4 : skb->len - skb->data_len
* %o5 : skb->len - skb->data_len * %o5 : skb->data
*/ */
#ifndef __ASSEMBLER__ #ifndef __ASSEMBLER__

4
arch/sparc/net/bpf_jit_asm.S
View File

@ -30,7 +30,7 @@ bpf_jit_load_word_positive_offset:
bne load_word_unaligned bne load_word_unaligned
nop nop
retl retl
ld [r_SKB_DATA + r_OFF], r_A ld [r_TMP], r_A
load_word_unaligned: load_word_unaligned:
ldub [r_TMP + 0x0], r_OFF ldub [r_TMP + 0x0], r_OFF
ldub [r_TMP + 0x1], r_TMP2 ldub [r_TMP + 0x1], r_TMP2
@ -59,7 +59,7 @@ bpf_jit_load_half_positive_offset:
bne load_half_unaligned bne load_half_unaligned
nop nop
retl retl
lduh [r_SKB_DATA + r_OFF], r_A lduh [r_TMP], r_A
load_half_unaligned: load_half_unaligned:
ldub [r_TMP + 0x0], r_OFF ldub [r_TMP + 0x0], r_OFF
ldub [r_TMP + 0x1], r_TMP2 ldub [r_TMP + 0x1], r_TMP2

2
arch/sparc/net/bpf_jit_comp.c
View File

@ -378,7 +378,7 @@ void bpf_jit_compile(struct sk_filter *fp)
emit_clear(r_X); emit_clear(r_X);
/* If this filter needs to access skb data, /* If this filter needs to access skb data,
* load %o4 and %o4 with: * load %o4 and %o5 with:
* %o4 = skb->len - skb->data_len * %o4 = skb->len - skb->data_len
* %o5 = skb->data * %o5 = skb->data
* And also back up %o7 into r_saved_O7 so we can * And also back up %o7 into r_saved_O7 so we can