From 171b53380085b1288b03b19a2b978f36a5c003d0 Mon Sep 17 00:00:00 2001 From: rwmjones Date: Fri, 7 Oct 2016 13:56:27 +0100 Subject: [PATCH] architecture: Add support for the RISC-V architecture. (#4305) RISC-V is an open source ISA in development since 2010 at UCB. For more information, see https://riscv.org/ I am adding RISC-V support to Fedora: https://fedoraproject.org/wiki/Architectures/RISC-V There are three major variants of the architecture (32-, 64- and 128-bit). The 128-bit variant is a paper exercise, but the other two really exist in silicon. RISC-V is always little endian. On Linux, the default kernel uname(2) can return "riscv" for all variants. However a patch was added recently which makes the kernel return one of "riscv32" or "riscv64" (or in future "riscv128"). So systemd should be prepared to handle any of "riscv", "riscv32" or "riscv64" (in future, "riscv128" but that is not included in the current patch). If the kernel returns "riscv" then you need to use the pointer size in order to know the real variant. The Fedora/RISC-V kernel only ever returns "riscv64" since we're only doing Fedora for 64 bit at the moment, and we've patched the kernel so it doesn't return "riscv". As well as the major bitsize variants, there are also architecture extensions. However I'm trying to ensure that uname(2) does *not* return any other information about those in utsname.machine, so that we don't end up with "riscv64abcde" nonsense. Instead those extensions will be exposed in /proc/cpuinfo similar to how flags work in x86. --- src/basic/architecture.c | 10 ++++++++++ src/basic/architecture.h | 12 ++++++++++++ 2 files changed, 22 insertions(+) diff --git a/src/basic/architecture.c b/src/basic/architecture.c index b1c8e91..b74dc0d 100644 --- a/src/basic/architecture.c +++ b/src/basic/architecture.c @@ -123,6 +123,14 @@ int uname_architecture(void) { { "crisv32", ARCHITECTURE_CRIS }, #elif defined(__nios2__) { "nios2", ARCHITECTURE_NIOS2 }, +#elif defined(__riscv__) + { "riscv32", ARCHITECTURE_RISCV32 }, + { "riscv64", ARCHITECTURE_RISCV64 }, +# if __SIZEOF_POINTER__ == 4 + { "riscv", ARCHITECTURE_RISCV32 }, +# elif __SIZEOF_POINTER__ == 8 + { "riscv", ARCHITECTURE_RISCV64 }, +# endif #else #error "Please register your architecture here!" #endif @@ -174,6 +182,8 @@ static const char *const architecture_table[_ARCHITECTURE_MAX] = { [ARCHITECTURE_TILEGX] = "tilegx", [ARCHITECTURE_CRIS] = "cris", [ARCHITECTURE_NIOS2] = "nios2", + [ARCHITECTURE_RISCV32] = "riscv32", + [ARCHITECTURE_RISCV64] = "riscv64", }; DEFINE_STRING_TABLE_LOOKUP(architecture, int); diff --git a/src/basic/architecture.h b/src/basic/architecture.h index b3e4d85..5a77c31 100644 --- a/src/basic/architecture.h +++ b/src/basic/architecture.h @@ -58,6 +58,8 @@ enum { ARCHITECTURE_TILEGX, ARCHITECTURE_CRIS, ARCHITECTURE_NIOS2, + ARCHITECTURE_RISCV32, + ARCHITECTURE_RISCV64, _ARCHITECTURE_MAX, _ARCHITECTURE_INVALID = -1 }; @@ -191,6 +193,16 @@ int uname_architecture(void); #elif defined(__nios2__) # define native_architecture() ARCHITECTURE_NIOS2 # define LIB_ARCH_TUPLE "nios2-linux-gnu" +#elif defined(__riscv__) +# if __SIZEOF_POINTER__ == 4 +# define native_architecture() ARCHITECTURE_RISCV32 +# define LIB_ARCH_TUPLE "riscv32-linux-gnu" +# elif __SIZEOF_POINTER__ == 8 +# define native_architecture() ARCHITECTURE_RISCV64 +# define LIB_ARCH_TUPLE "riscv64-linux-gnu" +# else +# error "Unrecognized riscv architecture variant" +# endif #else # error "Please register your architecture here!" #endif -- 2.7.4