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https://github.com/golang/go
synced 2024-11-17 22:14:43 -07:00
runtime: handle volatility of CX when dynamically linking on linux/386
Mostly by avoiding CX entirely, sometimes by reloading it. I also vetted the assembly in other packages, it's all fine. Change-Id: I50059669aaaa04efa303cf22ac228f9d14d83db0 Reviewed-on: https://go-review.googlesource.com/16386 Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Michael Hudson-Doyle
parent
c8abb02178
commit
6056cc5df6
@ -45,7 +45,8 @@ notintel:
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MOVL $1, AX
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CPUID
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MOVL CX, runtime·cpuid_ecx(SB)
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MOVL CX, AX // Move to global variable clobbers CX when generating PIC
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MOVL AX, runtime·cpuid_ecx(SB)
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MOVL DX, runtime·cpuid_edx(SB)
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nocpuinfo:
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@ -90,14 +91,14 @@ needtls:
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ok:
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// set up m and g "registers"
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get_tls(BX)
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LEAL runtime·g0(SB), CX
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MOVL CX, g(BX)
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LEAL runtime·g0(SB), DX
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MOVL DX, g(BX)
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LEAL runtime·m0(SB), AX
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// save m->g0 = g0
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MOVL CX, m_g0(AX)
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MOVL DX, m_g0(AX)
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// save g0->m = m0
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MOVL AX, g_m(CX)
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MOVL AX, g_m(DX)
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CALL runtime·emptyfunc(SB) // fault if stack check is wrong
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@ -187,9 +188,9 @@ TEXT runtime·gogo(SB), NOSPLIT, $0-4
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// to keep running g.
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TEXT runtime·mcall(SB), NOSPLIT, $0-4
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MOVL fn+0(FP), DI
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get_tls(CX)
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MOVL g(CX), AX // save state in g->sched
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get_tls(DX)
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MOVL g(DX), AX // save state in g->sched
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MOVL 0(SP), BX // caller's PC
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MOVL BX, (g_sched+gobuf_pc)(AX)
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LEAL fn+0(FP), BX // caller's SP
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@ -197,14 +198,14 @@ TEXT runtime·mcall(SB), NOSPLIT, $0-4
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MOVL AX, (g_sched+gobuf_g)(AX)
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// switch to m->g0 & its stack, call fn
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MOVL g(CX), BX
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MOVL g(DX), BX
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MOVL g_m(BX), BX
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MOVL m_g0(BX), SI
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CMPL SI, AX // if g == m->g0 call badmcall
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JNE 3(PC)
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MOVL $runtime·badmcall(SB), AX
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JMP AX
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MOVL SI, g(CX) // g = m->g0
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MOVL SI, g(DX) // g = m->g0
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MOVL (g_sched+gobuf_sp)(SI), SP // sp = m->g0->sched.sp
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PUSHL AX
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MOVL DI, DX
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@ -255,6 +256,7 @@ switch:
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MOVL AX, (g_sched+gobuf_g)(AX)
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// switch to g0
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get_tls(CX)
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MOVL DX, g(CX)
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MOVL (g_sched+gobuf_sp)(DX), BX
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// make it look like mstart called systemstack on g0, to stop traceback
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@ -530,11 +532,13 @@ TEXT ·asmcgocall(SB),NOSPLIT,$0-12
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MOVL m_g0(BP), SI
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MOVL g(CX), DI
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CMPL SI, DI
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JEQ 4(PC)
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JEQ noswitch
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CALL gosave<>(SB)
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get_tls(CX)
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MOVL SI, g(CX)
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MOVL (g_sched+gobuf_sp)(SI), SP
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noswitch:
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// Now on a scheduling stack (a pthread-created stack).
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SUBL $32, SP
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ANDL $~15, SP // alignment, perhaps unnecessary
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@ -732,8 +736,8 @@ nobar:
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TEXT runtime·setcallerpc(SB),NOSPLIT,$4-8
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MOVL argp+0(FP),AX // addr of first arg
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MOVL pc+4(FP), BX
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MOVL -4(AX), CX
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CMPL CX, runtime·stackBarrierPC(SB)
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MOVL -4(AX), DX
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CMPL DX, runtime·stackBarrierPC(SB)
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JEQ setbar
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MOVL BX, -4(AX) // set calling pc
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RET
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@ -801,39 +805,39 @@ TEXT runtime·memhash_varlen(SB),NOSPLIT,$16-12
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// hash function using AES hardware instructions
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TEXT runtime·aeshash(SB),NOSPLIT,$0-16
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MOVL p+0(FP), AX // ptr to data
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MOVL s+8(FP), CX // size
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MOVL s+8(FP), BX // size
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LEAL ret+12(FP), DX
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JMP runtime·aeshashbody(SB)
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TEXT runtime·aeshashstr(SB),NOSPLIT,$0-12
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MOVL p+0(FP), AX // ptr to string object
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MOVL 4(AX), CX // length of string
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MOVL 4(AX), BX // length of string
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MOVL (AX), AX // string data
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LEAL ret+8(FP), DX
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JMP runtime·aeshashbody(SB)
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// AX: data
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// CX: length
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// BX: length
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// DX: address to put return value
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TEXT runtime·aeshashbody(SB),NOSPLIT,$0-0
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MOVL h+4(FP), X0 // 32 bits of per-table hash seed
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PINSRW $4, CX, X0 // 16 bits of length
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PINSRW $4, BX, X0 // 16 bits of length
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PSHUFHW $0, X0, X0 // replace size with its low 2 bytes repeated 4 times
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MOVO X0, X1 // save unscrambled seed
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PXOR runtime·aeskeysched(SB), X0 // xor in per-process seed
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AESENC X0, X0 // scramble seed
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CMPL CX, $16
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CMPL BX, $16
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JB aes0to15
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JE aes16
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CMPL CX, $32
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CMPL BX, $32
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JBE aes17to32
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CMPL CX, $64
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CMPL BX, $64
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JBE aes33to64
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JMP aes65plus
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aes0to15:
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TESTL CX, CX
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TESTL BX, BX
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JE aes0
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ADDL $16, AX
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@ -843,8 +847,8 @@ aes0to15:
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// 16 bytes loaded at this address won't cross
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// a page boundary, so we can load it directly.
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MOVOU -16(AX), X1
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ADDL CX, CX
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PAND masks<>(SB)(CX*8), X1
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ADDL BX, BX
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PAND masks<>(SB)(BX*8), X1
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final1:
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AESENC X0, X1 // scramble input, xor in seed
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@ -857,9 +861,9 @@ endofpage:
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// address ends in 1111xxxx. Might be up against
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// a page boundary, so load ending at last byte.
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// Then shift bytes down using pshufb.
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MOVOU -32(AX)(CX*1), X1
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ADDL CX, CX
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PSHUFB shifts<>(SB)(CX*8), X1
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MOVOU -32(AX)(BX*1), X1
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ADDL BX, BX
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PSHUFB shifts<>(SB)(BX*8), X1
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JMP final1
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aes0:
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@ -879,7 +883,7 @@ aes17to32:
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// load data to be hashed
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MOVOU (AX), X2
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MOVOU -16(AX)(CX*1), X3
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MOVOU -16(AX)(BX*1), X3
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// scramble 3 times
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AESENC X0, X2
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@ -907,8 +911,8 @@ aes33to64:
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MOVOU (AX), X4
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MOVOU 16(AX), X5
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MOVOU -32(AX)(CX*1), X6
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MOVOU -16(AX)(CX*1), X7
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MOVOU -32(AX)(BX*1), X6
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MOVOU -16(AX)(BX*1), X7
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AESENC X0, X4
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AESENC X1, X5
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@ -943,10 +947,10 @@ aes65plus:
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AESENC X3, X3
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// start with last (possibly overlapping) block
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MOVOU -64(AX)(CX*1), X4
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MOVOU -48(AX)(CX*1), X5
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MOVOU -32(AX)(CX*1), X6
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MOVOU -16(AX)(CX*1), X7
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MOVOU -64(AX)(BX*1), X4
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MOVOU -48(AX)(BX*1), X5
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MOVOU -32(AX)(BX*1), X6
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MOVOU -16(AX)(BX*1), X7
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// scramble state once
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AESENC X0, X4
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@ -955,8 +959,8 @@ aes65plus:
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AESENC X3, X7
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// compute number of remaining 64-byte blocks
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DECL CX
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SHRL $6, CX
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DECL BX
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SHRL $6, BX
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aesloop:
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// scramble state, xor in a block
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@ -976,7 +980,7 @@ aesloop:
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AESENC X7, X7
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ADDL $64, AX
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DECL CX
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DECL BX
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JNE aesloop
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// 2 more scrambles to finish
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@ -408,7 +408,7 @@ TEXT runtime·sigaltstack(SB),NOSPLIT,$-8
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// setldt(int entry, int address, int limit)
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TEXT runtime·setldt(SB),NOSPLIT,$32
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MOVL entry+0(FP), BX // entry
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MOVL address+4(FP), CX // base address
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MOVL address+4(FP), DX // base address
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#ifdef GOOS_android
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/*
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@ -416,8 +416,8 @@ TEXT runtime·setldt(SB),NOSPLIT,$32
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* address currently holds m->tls, which must be %gs:0xf8.
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* See cgo/gcc_android_386.c for the derivation of the constant.
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*/
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SUBL $0xf8, CX
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MOVL CX, 0(CX)
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SUBL $0xf8, DX
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MOVL DX, 0(DX)
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#else
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/*
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* When linking against the system libraries,
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@ -429,23 +429,23 @@ TEXT runtime·setldt(SB),NOSPLIT,$32
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* To accommodate that rewrite, we translate
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* the address here and bump the limit to 0xffffffff (no limit)
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* so that -4(GS) maps to 0(address).
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* Also, the final 0(GS) (current 4(CX)) has to point
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* Also, the final 0(GS) (current 4(DX)) has to point
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* to itself, to mimic ELF.
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*/
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ADDL $0x4, CX // address
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MOVL CX, 0(CX)
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ADDL $0x4, DX // address
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MOVL DX, 0(DX)
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// We copy the glibc dynamic linker behaviour of storing the
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// __kernel_vsyscall entry point at 0x10(GS) so that it can be invoked
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// by "CALL 0x10(GS)" in all situations, not only those where the
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// binary is actually dynamically linked.
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MOVL runtime·_vdso(SB), AX
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MOVL AX, 0x10(CX)
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MOVL AX, 0x10(DX)
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#endif
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// set up user_desc
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LEAL 16(SP), AX // struct user_desc
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MOVL BX, 0(AX)
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MOVL CX, 4(AX)
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MOVL DX, 4(AX)
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MOVL $0xfffff, 8(AX)
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MOVL $(SEG_32BIT|LIMIT_IN_PAGES|USEABLE|CONTENTS_DATA), 12(AX) // flag bits
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