From 5da5f47e6c65eda83e5433bd905c4df03be98596 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 6 Apr 2020 20:21:05 -0700 Subject: linux-user/ppc: Fix padding in mcontext_t for ppc64 The padding that was added in 95cda4c44ee was added to a union, and so it had no effect. This fixes misalignment errors detected by clang sanitizers for ppc64 and ppc64le. In addition, only ppc64 allocates space for VSX registers, so do not save them for ppc32. The kernel only has references to CONFIG_SPE in signal_32.c, so do not attempt to save them for ppc64. Fixes: 95cda4c44ee Signed-off-by: Richard Henderson Message-Id: <20200407032105.26711-1-richard.henderson@linaro.org> Acked-by: Laurent Vivier Signed-off-by: David Gibson --- linux-user/ppc/signal.c | 69 +++++++++++++++++++++---------------------------- 1 file changed, 29 insertions(+), 40 deletions(-) (limited to 'linux-user') diff --git a/linux-user/ppc/signal.c b/linux-user/ppc/signal.c index ecd9973..20a02c1 100644 --- a/linux-user/ppc/signal.c +++ b/linux-user/ppc/signal.c @@ -35,12 +35,26 @@ struct target_mcontext { target_ulong mc_gregs[48]; /* Includes fpscr. */ uint64_t mc_fregs[33]; + #if defined(TARGET_PPC64) /* Pointer to the vector regs */ target_ulong v_regs; + /* + * On ppc64, this mcontext structure is naturally *unaligned*, + * or rather it is aligned on a 8 bytes boundary but not on + * a 16 byte boundary. This pad fixes it up. This is why we + * cannot use ppc_avr_t, which would force alignment. This is + * also why the vector regs are referenced in the ABI by the + * v_regs pointer above so any amount of padding can be added here. + */ + target_ulong pad; + /* VSCR and VRSAVE are saved separately. Also reserve space for VSX. */ + struct { + uint64_t altivec[34 + 16][2]; + } mc_vregs; #else target_ulong mc_pad[2]; -#endif + /* We need to handle Altivec and SPE at the same time, which no kernel needs to do. Fortunately, the kernel defines this bit to be Altivec-register-large all the time, rather than trying to @@ -48,32 +62,14 @@ struct target_mcontext { union { /* SPE vector registers. One extra for SPEFSCR. */ uint32_t spe[33]; - /* Altivec vector registers. The packing of VSCR and VRSAVE - varies depending on whether we're PPC64 or not: PPC64 splits - them apart; PPC32 stuffs them together. - We also need to account for the VSX registers on PPC64 - */ -#if defined(TARGET_PPC64) -#define QEMU_NVRREG (34 + 16) - /* On ppc64, this mcontext structure is naturally *unaligned*, - * or rather it is aligned on a 8 bytes boundary but not on - * a 16 bytes one. This pad fixes it up. This is also why the - * vector regs are referenced by the v_regs pointer above so - * any amount of padding can be added here - */ - target_ulong pad; -#else - /* On ppc32, we are already aligned to 16 bytes */ -#define QEMU_NVRREG 33 -#endif - /* We cannot use ppc_avr_t here as we do *not* want the implied - * 16-bytes alignment that would result from it. This would have - * the effect of making the whole struct target_mcontext aligned - * which breaks the layout of struct target_ucontext on ppc64. + /* + * Altivec vector registers. One extra for VRSAVE. + * On ppc32, we are already aligned to 16 bytes. We could + * use ppc_avr_t, but choose to share the same type as ppc64. */ - uint64_t altivec[QEMU_NVRREG][2]; -#undef QEMU_NVRREG + uint64_t altivec[33][2]; } mc_vregs; +#endif }; /* See arch/powerpc/include/asm/sigcontext.h. */ @@ -278,6 +274,7 @@ static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame) __put_user((uint32_t)env->spr[SPR_VRSAVE], vrsave); } +#if defined(TARGET_PPC64) /* Save VSX second halves */ if (env->insns_flags2 & PPC2_VSX) { uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34]; @@ -286,6 +283,7 @@ static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame) __put_user(*vsrl, &vsregs[i]); } } +#endif /* Save floating point registers. */ if (env->insns_flags & PPC_FLOAT) { @@ -296,22 +294,18 @@ static void save_user_regs(CPUPPCState *env, struct target_mcontext *frame) __put_user((uint64_t) env->fpscr, &frame->mc_fregs[32]); } +#if !defined(TARGET_PPC64) /* Save SPE registers. The kernel only saves the high half. */ if (env->insns_flags & PPC_SPE) { -#if defined(TARGET_PPC64) - for (i = 0; i < ARRAY_SIZE(env->gpr); i++) { - __put_user(env->gpr[i] >> 32, &frame->mc_vregs.spe[i]); - } -#else for (i = 0; i < ARRAY_SIZE(env->gprh); i++) { __put_user(env->gprh[i], &frame->mc_vregs.spe[i]); } -#endif /* Set MSR_SPE in the saved MSR value to indicate that frame->mc_vregs contains valid data. */ msr |= MSR_SPE; __put_user(env->spe_fscr, &frame->mc_vregs.spe[32]); } +#endif /* Store MSR. */ __put_user(msr, &frame->mc_gregs[TARGET_PT_MSR]); @@ -392,6 +386,7 @@ static void restore_user_regs(CPUPPCState *env, __get_user(env->spr[SPR_VRSAVE], vrsave); } +#if defined(TARGET_PPC64) /* Restore VSX second halves */ if (env->insns_flags2 & PPC2_VSX) { uint64_t *vsregs = (uint64_t *)&frame->mc_vregs.altivec[34]; @@ -400,6 +395,7 @@ static void restore_user_regs(CPUPPCState *env, __get_user(*vsrl, &vsregs[i]); } } +#endif /* Restore floating point registers. */ if (env->insns_flags & PPC_FLOAT) { @@ -412,22 +408,15 @@ static void restore_user_regs(CPUPPCState *env, env->fpscr = (uint32_t) fpscr; } +#if !defined(TARGET_PPC64) /* Save SPE registers. The kernel only saves the high half. */ if (env->insns_flags & PPC_SPE) { -#if defined(TARGET_PPC64) - for (i = 0; i < ARRAY_SIZE(env->gpr); i++) { - uint32_t hi; - - __get_user(hi, &frame->mc_vregs.spe[i]); - env->gpr[i] = ((uint64_t)hi << 32) | ((uint32_t) env->gpr[i]); - } -#else for (i = 0; i < ARRAY_SIZE(env->gprh); i++) { __get_user(env->gprh[i], &frame->mc_vregs.spe[i]); } -#endif __get_user(env->spe_fscr, &frame->mc_vregs.spe[32]); } +#endif } #if !defined(TARGET_PPC64) -- cgit v1.1