From 21657ad4f01a634beac570c64c0691e51b9cf366 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Sat, 6 Mar 2021 21:41:48 +0000 Subject: [PATCH] xen: Bump the minimum version of GCC supported to 4.9 for arm32 and 5.1 on arm64 Compilers older than 4.8 have known codegen issues which can lead to silent miscompilation: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 Furthermore, pre-4.9 GCC have known bugs (including things like internal compiler errors on Arm) which would require workaround (I haven't checked if we have any in Xen). The minimum version of GCC to build the hypervisor on arm is now raised to 4.9. In addition to that, on arm64, GCC version >= 4.9 and < 5.1 have been shown to emit memory references beyond the stack pointer, resulting in memory corruption if an interrupt is taken after the stack pointer has been adjusted but before the reference has been executed. Therefore, the minimum for arm64 is raised to 5.1. Signed-off-by: Julien Grall Reviewed-by: Bertrand Marquis Reviewed-by: Stefano Stabellini Release-Acked-by: Ian Jackson --- README | 7 +++++-- xen/include/xen/compiler.h | 10 ++++++++++ 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/README b/README index 8c99c30986..aa8b4fe126 100644 --- a/README +++ b/README @@ -42,8 +42,11 @@ provided by your OS distributor: - GNU Binutils 2.16.91.0.5 or later or - Clang/LLVM 3.5 or later - - For ARM: - - GCC 4.8 or later + - For ARM 32-bit: + - GCC 4.9 or later + - GNU Binutils 2.24 or later + - For ARM 64-bit: + - GCC 5.1 or later - GNU Binutils 2.24 or later * Development install of zlib (e.g., zlib-dev) * Development install of Python 2.6 or later (e.g., python-dev) diff --git a/xen/include/xen/compiler.h b/xen/include/xen/compiler.h index 0ec0b4698e..17cf00e1ec 100644 --- a/xen/include/xen/compiler.h +++ b/xen/include/xen/compiler.h @@ -3,6 +3,16 @@ #if !defined(__GNUC__) || (__GNUC__ < 4) #error Sorry, your compiler is too old/not recognized. +#elif CONFIG_CC_IS_GCC +# if defined(CONFIG_ARM_32) && CONFIG_GCC_VERSION < 40900 +# error Sorry, your version of GCC is too old - please use 4.9 or newer. +# elif defined(CONFIG_ARM_64) && CONFIG_GCC_VERSION < 50100 +/* + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63293 + * https://lore.kernel.org/r/20210107111841.GN1551@shell.armlinux.org.uk + */ +# error Sorry, your version of GCC is too old - please use 5.1 or newer. +# endif #endif #define barrier() __asm__ __volatile__("": : :"memory") -- 2.30.2