From 4d6e1c6495f483e8c48526189c4c6984b44365fc Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Fri, 23 Jun 2023 11:15:44 +0100 Subject: include/exec/memattrs: Add two bits of space to MemTxAttrs We will need 2 bits to represent ARMSecurityState. Do not attempt to replace or widen secure, even though it logically overlaps the new field -- there are uses within e.g. hw/block/pflash_cfi01.c, which don't know anything specific about ARM. Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson Message-id: 20230620124418.805717-7-richard.henderson@linaro.org Signed-off-by: Peter Maydell --- include/exec/memattrs.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/exec/memattrs.h b/include/exec/memattrs.h index 9fb98bc..d04170a 100644 --- a/include/exec/memattrs.h +++ b/include/exec/memattrs.h @@ -29,10 +29,17 @@ typedef struct MemTxAttrs { * "didn't specify" if necessary. */ unsigned int unspecified:1; - /* ARM/AMBA: TrustZone Secure access + /* + * ARM/AMBA: TrustZone Secure access * x86: System Management Mode access */ unsigned int secure:1; + /* + * ARM: ArmSecuritySpace. This partially overlaps secure, but it is + * easier to have both fields to assist code that does not understand + * ARMv9 RME, or no specific knowledge of ARM at all (e.g. pflash). + */ + unsigned int space:2; /* Memory access is usermode (unprivileged) */ unsigned int user:1; /* -- cgit v1.1 From b0438861efe1dfbdfdd9fa1d9aa05100d37ea8ee Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Thu, 22 Jun 2023 14:08:23 +0100 Subject: host-utils: Avoid using __builtin_subcll on buggy versions of Apple Clang MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We use __builtin_subcll() to do a 64-bit subtract with borrow-in and borrow-out when the host compiler supports it. Unfortunately some versions of Apple Clang have a bug in their implementation of this intrinsic which means it returns the wrong value. The effect is that a QEMU built with the affected compiler will hang when emulating x86 or m68k float80 division. The upstream LLVM issue is: https://github.com/llvm/llvm-project/issues/55253 The commit that introduced the bug apparently never made it into an upstream LLVM release without the subsequent fix https://github.com/llvm/llvm-project/commit/fffb6e6afdbaba563189c1f715058ed401fbc88d but unfortunately it did make it into Apple Clang 14.0, as shipped in Xcode 14.3 (14.2 is reported to be OK). The Apple bug number is FB12210478. Add ifdefs to avoid use of __builtin_subcll() on Apple Clang version 14 or greater. There is not currently a version of Apple Clang which has the bug fix -- when one appears we should be able to add an upper bound to the ifdef condition so we can start using the builtin again. We make the lower bound a conservative "any Apple clang with major version 14 or greater" because the consequences of incorrectly disabling the builtin when it would work are pretty small and the consequences of not disabling it when we should are pretty bad. Many thanks to those users who both reported this bug and also did a lot of work in identifying the root cause; in particular to Daniel Bertalan and osy. Cc: qemu-stable@nongnu.org Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1631 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1659 Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Reviewed-by: Daniel P. Berrangé Tested-by: Daniel Bertalan Tested-by: Tested-By: Solra Bizna Message-id: 20230622130823.1631719-1-peter.maydell@linaro.org --- include/qemu/compiler.h | 13 +++++++++++++ include/qemu/host-utils.h | 2 +- 2 files changed, 14 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index c2f49df..a309f90 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -184,4 +184,17 @@ #define QEMU_DISABLE_CFI #endif +/* + * Apple clang version 14 has a bug in its __builtin_subcll(); define + * BUILTIN_SUBCLL_BROKEN for the offending versions so we can avoid it. + * When a version of Apple clang which has this bug fixed is released + * we can add an upper bound to this check. + * See https://gitlab.com/qemu-project/qemu/-/issues/1631 + * and https://gitlab.com/qemu-project/qemu/-/issues/1659 for details. + * The bug never made it into any upstream LLVM releases, only Apple ones. + */ +#if defined(__apple_build_version__) && __clang_major__ >= 14 +#define BUILTIN_SUBCLL_BROKEN +#endif + #endif /* COMPILER_H */ diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index d3b4dce..0116183 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -649,7 +649,7 @@ static inline uint64_t uadd64_carry(uint64_t x, uint64_t y, bool *pcarry) */ static inline uint64_t usub64_borrow(uint64_t x, uint64_t y, bool *pborrow) { -#if __has_builtin(__builtin_subcll) +#if __has_builtin(__builtin_subcll) && !defined(BUILTIN_SUBCLL_BROKEN) unsigned long long b = *pborrow; x = __builtin_subcll(x, y, b, &b); *pborrow = b & 1; -- cgit v1.1