From 9da06535092d6d9dec442641a26c64bce5574322 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Sun, 24 Jun 2018 14:08:59 +0200
Subject: [PATCH 47/72] ARM64: Fix exit stub patching.
Contributed by Javier Guerra Giraldez.
---
src/lj_asm_arm64.h | 64 +++++++++++++++++++++++++------------------
src/lj_emit_arm64.h | 18 ++++++------
src/lj_target_arm64.h | 7 +++--
3 files changed, 51 insertions(+), 38 deletions(-)
diff --git a/src/lj_asm_arm64.h b/src/lj_asm_arm64.h
index cbb186d..baafa21 100644
--- a/src/lj_asm_arm64.h
+++ b/src/lj_asm_arm64.h
@@ -56,11 +56,11 @@ static void asm_exitstub_setup(ASMState *as, ExitNo nexits)
asm_mclimit(as);
/* 1: str lr,[sp]; bl ->vm_exit_handler; movz w0,traceno; bl <1; bl <1; ... */
for (i = nexits-1; (int32_t)i >= 0; i--)
- *--mxp = A64I_LE(A64I_BL|((-3-i)&0x03ffffffu));
- *--mxp = A64I_LE(A64I_MOVZw|A64F_U16(as->T->traceno));
+ *--mxp = A64I_LE(A64I_BL | A64F_S26(-3-i));
+ *--mxp = A64I_LE(A64I_MOVZw | A64F_U16(as->T->traceno));
mxp--;
- *mxp = A64I_LE(A64I_BL|(((MCode *)(void *)lj_vm_exit_handler-mxp)&0x03ffffffu));
- *--mxp = A64I_LE(A64I_STRx|A64F_D(RID_LR)|A64F_N(RID_SP));
+ *mxp = A64I_LE(A64I_BL | A64F_S26(((MCode *)(void *)lj_vm_exit_handler-mxp)));
+ *--mxp = A64I_LE(A64I_STRx | A64F_D(RID_LR) | A64F_N(RID_SP));
as->mctop = mxp;
}
@@ -77,7 +77,7 @@ static void asm_guardcc(ASMState *as, A64CC cc)
MCode *p = as->mcp;
if (LJ_UNLIKELY(p == as->invmcp)) {
as->loopinv = 1;
- *p = A64I_B | ((target-p) & 0x03ffffffu);
+ *p = A64I_B | A64F_S26(target-p);
emit_cond_branch(as, cc^1, p-1);
return;
}
@@ -91,7 +91,7 @@ static void asm_guardtnb(ASMState *as, A64Ins ai, Reg r, uint32_t bit)
MCode *p = as->mcp;
if (LJ_UNLIKELY(p == as->invmcp)) {
as->loopinv = 1;
- *p = A64I_B | ((target-p) & 0x03ffffffu);
+ *p = A64I_B | A64F_S26(target-p);
emit_tnb(as, ai^0x01000000u, r, bit, p-1);
return;
}
@@ -105,7 +105,7 @@ static void asm_guardcnb(ASMState *as, A64Ins ai, Reg r)
MCode *p = as->mcp;
if (LJ_UNLIKELY(p == as->invmcp)) {
as->loopinv = 1;
- *p = A64I_B | ((target-p) & 0x03ffffffu);
+ *p = A64I_B | A64F_S26(target-p);
emit_cnb(as, ai^0x01000000u, r, p-1);
return;
}
@@ -1850,7 +1850,7 @@ static void asm_loop_fixup(ASMState *as)
p[-2] |= ((uint32_t)delta & mask) << 5;
} else {
ptrdiff_t delta = target - (p - 1);
- p[-1] = A64I_B | ((uint32_t)(delta) & 0x03ffffffu);
+ p[-1] = A64I_B | A64F_S26(delta);
}
}
@@ -1919,7 +1919,7 @@ static void asm_tail_fixup(ASMState *as, TraceNo lnk)
}
/* Patch exit branch. */
target = lnk ? traceref(as->J, lnk)->mcode : (MCode *)lj_vm_exit_interp;
- p[-1] = A64I_B | (((target-p)+1)&0x03ffffffu);
+ p[-1] = A64I_B | A64F_S26((target-p)+1);
}
/* Prepare tail of code. */
@@ -1982,40 +1982,50 @@ void lj_asm_patchexit(jit_State *J, GCtrace *T, ExitNo exitno, MCode *target)
{
MCode *p = T->mcode;
MCode *pe = (MCode *)((char *)p + T->szmcode);
- MCode *cstart = NULL, *cend = p;
+ MCode *cstart = NULL;
MCode *mcarea = lj_mcode_patch(J, p, 0);
MCode *px = exitstub_trace_addr(T, exitno);
+ /* Note: this assumes a trace exit is only ever patched once. */
for (; p < pe; p++) {
/* Look for exitstub branch, replace with branch to target. */
+ ptrdiff_t delta = target - p;
MCode ins = A64I_LE(*p);
if ((ins & 0xff000000u) == 0x54000000u &&
((ins ^ ((px-p)<<5)) & 0x00ffffe0u) == 0) {
- /* Patch bcc exitstub. */
- *p = A64I_LE((ins & 0xff00001fu) | (((target-p)<<5) & 0x00ffffe0u));
- cend = p+1;
- if (!cstart) cstart = p;
+ /* Patch bcc, if within range. */
+ if (A64F_S_OK(delta, 19)) {
+ *p = A64I_LE((ins & 0xff00001fu) | A64F_S19(delta));
+ if (!cstart) cstart = p;
+ }
} else if ((ins & 0xfc000000u) == 0x14000000u &&
((ins ^ (px-p)) & 0x03ffffffu) == 0) {
- /* Patch b exitstub. */
- *p = A64I_LE((ins & 0xfc000000u) | ((target-p) & 0x03ffffffu));
- cend = p+1;
+ /* Patch b. */
+ lua_assert(A64F_S_OK(delta, 26));
+ *p = A64I_LE((ins & 0xfc000000u) | A64F_S26(delta));
if (!cstart) cstart = p;
} else if ((ins & 0x7e000000u) == 0x34000000u &&
((ins ^ ((px-p)<<5)) & 0x00ffffe0u) == 0) {
- /* Patch cbz/cbnz exitstub. */
- *p = A64I_LE((ins & 0xff00001f) | (((target-p)<<5) & 0x00ffffe0u));
- cend = p+1;
- if (!cstart) cstart = p;
+ /* Patch cbz/cbnz, if within range. */
+ if (A64F_S_OK(delta, 19)) {
+ *p = A64I_LE((ins & 0xff00001fu) | A64F_S19(delta));
+ if (!cstart) cstart = p;
+ }
} else if ((ins & 0x7e000000u) == 0x36000000u &&
((ins ^ ((px-p)<<5)) & 0x0007ffe0u) == 0) {
- /* Patch tbz/tbnz exitstub. */
- *p = A64I_LE((ins & 0xfff8001fu) | (((target-p)<<5) & 0x0007ffe0u));
- cend = p+1;
- if (!cstart) cstart = p;
+ /* Patch tbz/tbnz, if within range. */
+ if (A64F_S_OK(delta, 14)) {
+ *p = A64I_LE((ins & 0xfff8001fu) | A64F_S14(delta));
+ if (!cstart) cstart = p;
+ }
}
}
- lua_assert(cstart != NULL);
- lj_mcode_sync(cstart, cend);
+ { /* Always patch long-range branch in exit stub itself. */
+ ptrdiff_t delta = target - px;
+ lua_assert(A64F_S_OK(delta, 26));
+ *px = A64I_B | A64F_S26(delta);
+ if (!cstart) cstart = px;
+ }
+ lj_mcode_sync(cstart, px+1);
lj_mcode_patch(J, mcarea, 1);
}
diff --git a/src/lj_emit_arm64.h b/src/lj_emit_arm64.h
index 6da4c7d..1001b1d 100644
--- a/src/lj_emit_arm64.h
+++ b/src/lj_emit_arm64.h
@@ -241,7 +241,7 @@ static void emit_loadk(ASMState *as, Reg rd, uint64_t u64, int is64)
#define mcpofs(as, k) \
((intptr_t)((uintptr_t)(k) - (uintptr_t)(as->mcp - 1)))
#define checkmcpofs(as, k) \
- ((((mcpofs(as, k)>>2) + 0x00040000) >> 19) == 0)
+ (A64F_S_OK(mcpofs(as, k)>>2, 19))
static Reg ra_allock(ASMState *as, intptr_t k, RegSet allow);
@@ -312,7 +312,7 @@ static void emit_cond_branch(ASMState *as, A64CC cond, MCode *target)
{
MCode *p = --as->mcp;
ptrdiff_t delta = target - p;
- lua_assert(((delta + 0x40000) >> 19) == 0);
+ lua_assert(A64F_S_OK(delta, 19));
*p = A64I_BCC | A64F_S19(delta) | cond;
}
@@ -320,24 +320,24 @@ static void emit_branch(ASMState *as, A64Ins ai, MCode *target)
{
MCode *p = --as->mcp;
ptrdiff_t delta = target - p;
- lua_assert(((delta + 0x02000000) >> 26) == 0);
- *p = ai | ((uint32_t)delta & 0x03ffffffu);
+ lua_assert(A64F_S_OK(delta, 26));
+ *p = ai | A64F_S26(delta);
}
static void emit_tnb(ASMState *as, A64Ins ai, Reg r, uint32_t bit, MCode *target)
{
MCode *p = --as->mcp;
ptrdiff_t delta = target - p;
- lua_assert(bit < 63 && ((delta + 0x2000) >> 14) == 0);
+ lua_assert(bit < 63 && A64F_S_OK(delta, 14));
if (bit > 31) ai |= A64I_X;
- *p = ai | A64F_BIT(bit & 31) | A64F_S14((uint32_t)delta & 0x3fffu) | r;
+ *p = ai | A64F_BIT(bit & 31) | A64F_S14(delta) | r;
}
static void emit_cnb(ASMState *as, A64Ins ai, Reg r, MCode *target)
{
MCode *p = --as->mcp;
ptrdiff_t delta = target - p;
- lua_assert(((delta + 0x40000) >> 19) == 0);
+ lua_assert(A64F_S_OK(delta, 19));
*p = ai | A64F_S19(delta) | r;
}
@@ -347,8 +347,8 @@ static void emit_call(ASMState *as, void *target)
{
MCode *p = --as->mcp;
ptrdiff_t delta = (char *)target - (char *)p;
- if ((((delta>>2) + 0x02000000) >> 26) == 0) {
- *p = A64I_BL | ((uint32_t)(delta>>2) & 0x03ffffffu);
+ if (A64F_S_OK(delta>>2, 26)) {
+ *p = A64I_BL | A64F_S26(delta>>2);
} else { /* Target out of range: need indirect call. But don't use R0-R7. */
Reg r = ra_allock(as, i64ptr(target),
RSET_RANGE(RID_X8, RID_MAX_GPR)-RSET_FIXED);
diff --git a/src/lj_target_arm64.h b/src/lj_target_arm64.h
index 520023a..a207a2b 100644
--- a/src/lj_target_arm64.h
+++ b/src/lj_target_arm64.h
@@ -132,9 +132,9 @@ static LJ_AINLINE uint32_t *exitstub_trace_addr_(uint32_t *p, uint32_t exitno)
#define A64F_IMMR(x) ((x) << 16)
#define A64F_U16(x) ((x) << 5)
#define A64F_U12(x) ((x) << 10)
-#define A64F_S26(x) (x)
+#define A64F_S26(x) (((uint32_t)(x) & 0x03ffffffu))
#define A64F_S19(x) (((uint32_t)(x) & 0x7ffffu) << 5)
-#define A64F_S14(x) ((x) << 5)
+#define A64F_S14(x) (((uint32_t)(x) & 0x3fffu) << 5)
#define A64F_S9(x) ((x) << 12)
#define A64F_BIT(x) ((x) << 19)
#define A64F_SH(sh, x) (((sh) << 22) | ((x) << 10))
@@ -145,6 +145,9 @@ static LJ_AINLINE uint32_t *exitstub_trace_addr_(uint32_t *p, uint32_t exitno)
#define A64F_LSL16(x) (((x) / 16) << 21)
#define A64F_BSH(sh) ((sh) << 10)
+/* Check for valid field range. */
+#define A64F_S_OK(x, b) ((((x) + (1 << (b-1))) >> (b)) == 0)
+
typedef enum A64Ins {
A64I_S = 0x20000000,
A64I_X = 0x80000000,
--
2.20.1