87 lines
2.4 KiB
ArmAsm
87 lines
2.4 KiB
ArmAsm
# mach: bpf
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# sim: --skb-data-offset=0x20
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# output: pass\nexit 0 (0x0)\n
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;;; ldabs.s
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;;; Tests for non-generic BPF load instructions in simulator.
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;;; These instructions (ld{abs,ind}{b,h,w,dw}) are used to access
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;;; kernel socket data from BPF programs for high performance filters.
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;;;
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;;; Register r6 is an implicit input holding a pointer to a struct sk_buff.
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;;; Register r0 is an implicit output, holding the fetched data.
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;;;
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;;; e.g.
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;;; ldabsw means:
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;;; r0 = ntohl (*(u32 *) (((struct sk_buff *)r6)->data + imm32))
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;;;
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;;; ldindw means
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;;; r0 = ntohl (*(u32 *) (((struct sk_buff *)r6)->data + src_reg + imm32))
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.include "testutils.inc"
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.text
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.global main
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.type main, @function
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main:
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;; R6 holds a pointer to a struct sk_buff, which we pretend
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;; exists at 0x1000
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mov %r6, 0x1000
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;; We configure skb-data-offset=0x20
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;; This specifies offsetof(struct sk_buff, data), where the field 'data'
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;; is a pointer a data buffer, in this case at 0x2000
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stw [%r6+0x20], 0x2000
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;; Write the value 0x7eadbeef into memory at 0x2004
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;; i.e. offset 4 within the data buffer pointed to by
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;; ((struct sk_buff *)r6)->data
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stw [%r6+0x1004], 0xdeadbeef
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;; Now load data[4] into r0 using the ldabsw instruction
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ldabsw 0x4
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;; ...and compare to what we expect
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fail_ne32 %r0, 0xdeadbeef
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;; Repeat for a half-word (2-bytes)
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sth [%r6+0x1008], 0x1234
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ldabsh 0x8
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fail_ne32 %r0, 0x1234
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;; Repeat for a single byte
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stb [%r6+0x1010], 0x5a
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ldabsb 0x10
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fail_ne32 %r0, 0x5a
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;; Repeat for a double-word (8-byte)
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;; (note: fail_ne macro uses r0, so copy to another r1 to compare)
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lddw %r2, 0x1234deadbeef5678
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stxdw [%r6+0x1018], %r2
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ldabsdw 0x18
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mov %r1, %r0
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fail_ne %r1, 0x1234deadbeef5678
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;; Now, we do the same for the indirect loads
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mov %r7, 0x100
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stw [%r6+0x1100], 0xfeedbeef
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ldindw %r7, 0x0
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fail_ne32 %r0, 0xfeedbeef
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;; half-word
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sth [%r6+0x1104], 0x6789
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ldindh %r7, 0x4
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fail_ne32 %r0, 0x6789
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;; byte
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stb [%r6+0x1108], 0x5f
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ldindb %r7, 0x8
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fail_ne32 %r0, 0x5f
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;; double-word
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lddw %r2, 0xcafe12345678d00d
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stxdw [%r6+0x1110], %r2
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ldinddw %r7, 0x10
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mov %r1, %r0
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fail_ne %r1, 0xcafe12345678d00d
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pass
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