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Re: [Qemu-devel] [PATCH v3 15/16] tcg/ppc: Return false on failure from
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH v3 15/16] tcg/ppc: Return false on failure from patch_reloc |
Date: |
Mon, 03 Dec 2018 10:44:30 +0000 |
User-agent: |
mu4e 1.1.0; emacs 26.1.90 |
Richard Henderson <address@hidden> writes:
> The reloc_pc{14,24}_val routines retain their asserts.
> Use these directly within the slow paths.
>
> Signed-off-by: Richard Henderson <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
> ---
> tcg/ppc/tcg-target.inc.c | 32 +++++++++++++++++++++-----------
> 1 file changed, 21 insertions(+), 11 deletions(-)
>
> diff --git a/tcg/ppc/tcg-target.inc.c b/tcg/ppc/tcg-target.inc.c
> index 860b0d36e1..8c1cfdd7ac 100644
> --- a/tcg/ppc/tcg-target.inc.c
> +++ b/tcg/ppc/tcg-target.inc.c
> @@ -193,9 +193,14 @@ static uint32_t reloc_pc24_val(tcg_insn_unit *pc,
> tcg_insn_unit *target)
> return disp & 0x3fffffc;
> }
>
> -static void reloc_pc24(tcg_insn_unit *pc, tcg_insn_unit *target)
> +static bool reloc_pc24(tcg_insn_unit *pc, tcg_insn_unit *target)
> {
> - *pc = (*pc & ~0x3fffffc) | reloc_pc24_val(pc, target);
> + ptrdiff_t disp = tcg_ptr_byte_diff(target, pc);
> + if (in_range_b(disp)) {
> + *pc = (*pc & ~0x3fffffc) | (disp & 0x3fffffc);
> + return true;
> + }
> + return false;
> }
>
> static uint16_t reloc_pc14_val(tcg_insn_unit *pc, tcg_insn_unit *target)
> @@ -205,9 +210,14 @@ static uint16_t reloc_pc14_val(tcg_insn_unit *pc,
> tcg_insn_unit *target)
> return disp & 0xfffc;
> }
>
> -static void reloc_pc14(tcg_insn_unit *pc, tcg_insn_unit *target)
> +static bool reloc_pc14(tcg_insn_unit *pc, tcg_insn_unit *target)
> {
> - *pc = (*pc & ~0xfffc) | reloc_pc14_val(pc, target);
> + ptrdiff_t disp = tcg_ptr_byte_diff(target, pc);
> + if (disp == (int16_t) disp) {
> + *pc = (*pc & ~0xfffc) | (disp & 0xfffc);
> + return true;
> + }
> + return false;
> }
>
> /* parse target specific constraints */
> @@ -524,11 +534,9 @@ static bool patch_reloc(tcg_insn_unit *code_ptr, int
> type,
>
> switch (type) {
> case R_PPC_REL14:
> - reloc_pc14(code_ptr, target);
> - break;
> + return reloc_pc14(code_ptr, target);
> case R_PPC_REL24:
> - reloc_pc24(code_ptr, target);
> - break;
> + return reloc_pc24(code_ptr, target);
> case R_PPC_ADDR16:
> /* We are abusing this relocation type. This points to a pair
> of insns, addis + load. If the displacement is small, we
> @@ -540,7 +548,9 @@ static bool patch_reloc(tcg_insn_unit *code_ptr, int type,
> } else {
> int16_t lo = value;
> int hi = value - lo;
> - assert(hi + lo == value);
> + if (hi + lo != value) {
> + return false;
> + }
> code_ptr[0] = deposit32(code_ptr[0], 0, 16, hi >> 16);
> code_ptr[1] = deposit32(code_ptr[1], 0, 16, lo);
> }
> @@ -1638,7 +1648,7 @@ static void tcg_out_qemu_ld_slow_path(TCGContext *s,
> TCGLabelQemuLdst *lb)
> TCGMemOp opc = get_memop(oi);
> TCGReg hi, lo, arg = TCG_REG_R3;
>
> - reloc_pc14(lb->label_ptr[0], s->code_ptr);
> + **lb->label_ptr |= reloc_pc14_val(*lb->label_ptr, s->code_ptr);
>
> tcg_out_mov(s, TCG_TYPE_PTR, arg++, TCG_AREG0);
>
> @@ -1683,7 +1693,7 @@ static void tcg_out_qemu_st_slow_path(TCGContext *s,
> TCGLabelQemuLdst *lb)
> TCGMemOp s_bits = opc & MO_SIZE;
> TCGReg hi, lo, arg = TCG_REG_R3;
>
> - reloc_pc14(lb->label_ptr[0], s->code_ptr);
> + **lb->label_ptr |= reloc_pc14_val(*lb->label_ptr, s->code_ptr);
>
> tcg_out_mov(s, TCG_TYPE_PTR, arg++, TCG_AREG0);
--
Alex Bennée
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