19 Nov
2022
19 Nov
'22
2:02 p.m.
Added 32-bit RISC-V support. I have managed to get 32-bit RISC-V No-MMU
Linux running based on mainstream buildroot. It's nice to have uclibc
support this 32-bit No-MMU target.
There's no substantial code change except definations and config
options.
Signed-off-by: Yimin Gu <ustcymgu(a)gmail.com>
---
Rules.mak | 2 ++
extra/Configs/Config.in | 9 +++++++++
extra/Configs/Config.riscv32 | 14 ++++++++++++++
libc/sysdeps/linux/riscv32 | 1 +
libc/sysdeps/linux/riscv64/bits/wordsize.h | 3 ++-
libc/sysdeps/linux/riscv64/sys/asm.h | 6 +++++-
6 files changed, 33 insertions(+), 2 deletions(-)
create mode 100644 extra/Configs/Config.riscv32
create mode 120000 libc/sysdeps/linux/riscv32
diff --git a/Rules.mak b/Rules.mak
index 3fb64c728..71a14fc38 100644
--- a/Rules.mak
+++ b/Rules.mak
@@ -305,6 +305,7 @@ ifneq ($(TARGET_ARCH),c6x)
ifneq ($(TARGET_ARCH),h8300)
ifneq ($(TARGET_ARCH),arc)
ifneq ($(TARGET_ARCH),aarch64)
+ifneq ($(TARGET_ARCH),riscv32)
CPU_CFLAGS-y += -msoft-float
endif
endif
@@ -316,6 +317,7 @@ endif
endif
endif
endif
+endif
ifeq ($(TARGET_ARCH),aarch64)
CPU_CFLAGS-y += -ftls-model=initial-exec
diff --git a/extra/Configs/Config.in b/extra/Configs/Config.in
index a58ceb265..5e6af800d 100644
--- a/extra/Configs/Config.in
+++ b/extra/Configs/Config.in
@@ -39,6 +39,7 @@ choice
default TARGET_or1k if DESIRED_TARGET_ARCH = "or1k"
default TARGET_powerpc if DESIRED_TARGET_ARCH = "powerpc"
default TARGET_riscv64 if DESIRED_TARGET_ARCH = "riscv64"
+ default TARGET_riscv32 if DESIRED_TARGET_ARCH = "riscv32"
default TARGET_sh if DESIRED_TARGET_ARCH = "sh"
default TARGET_sparc if DESIRED_TARGET_ARCH = "sparc"
default TARGET_sparc64 if DESIRED_TARGET_ARCH = "sparc64"
@@ -125,6 +126,9 @@ config TARGET_powerpc
config TARGET_riscv64
bool "riscv64"
+config TARGET_riscv32
+ bool "riscv32"
+
config TARGET_sh
bool "superh"
@@ -240,6 +244,10 @@ if TARGET_riscv64
source "extra/Configs/Config.riscv64"
endif
+if TARGET_riscv32
+source "extra/Configs/Config.riscv32"
+endif
+
if TARGET_sh
source "extra/Configs/Config.sh"
endif
@@ -538,6 +546,7 @@ config UCLIBC_HAS_LINUXTHREADS
select UCLIBC_HAS_REALTIME
depends on !TARGET_aarch64 && \
!TARGET_riscv64 && \
+ !TARGET_riscv32 && \
!TARGET_metag
help
If you want to compile uClibc with Linuxthreads support, then answer Y.
diff --git a/extra/Configs/Config.riscv32 b/extra/Configs/Config.riscv32
new file mode 100644
index 000000000..304d30f70
--- /dev/null
+++ b/extra/Configs/Config.riscv32
@@ -0,0 +1,14 @@
+#
+# For a description of the syntax of this configuration file,
+# see extra/config/Kconfig-language.txt
+#
+
+config TARGET_ARCH
+ string
+ default "riscv32"
+
+config FORCE_OPTIONS_FOR_ARCH
+ bool
+ default y
+ select ARCH_LITTLE_ENDIAN
+ select ARCH_HAS_MMU
diff --git a/libc/sysdeps/linux/riscv32 b/libc/sysdeps/linux/riscv32
new file mode 120000
index 000000000..11677ef05
--- /dev/null
+++ b/libc/sysdeps/linux/riscv32
@@ -0,0 +1 @@
+riscv64
\ No newline at end of file
diff --git a/libc/sysdeps/linux/riscv64/bits/wordsize.h
b/libc/sysdeps/linux/riscv64/bits/wordsize.h
index 67a16ba62..1fc649aad 100644
--- a/libc/sysdeps/linux/riscv64/bits/wordsize.h
+++ b/libc/sysdeps/linux/riscv64/bits/wordsize.h
@@ -25,5 +25,6 @@
#if __riscv_xlen == 64
# define __WORDSIZE_TIME64_COMPAT32 1
#else
-# error "rv32i-based targets are not supported"
+# define __WORDSIZE_TIME64_COMPAT32 1
+// # warning "rv32i-based targets are experimental"
#endif
diff --git a/libc/sysdeps/linux/riscv64/sys/asm.h b/libc/sysdeps/linux/riscv64/sys/asm.h
index ddb84b683..3c94c9a70 100644
--- a/libc/sysdeps/linux/riscv64/sys/asm.h
+++ b/libc/sysdeps/linux/riscv64/sys/asm.h
@@ -26,7 +26,11 @@
# define REG_S sd
# define REG_L ld
#elif __riscv_xlen == 32
-# error "rv32i-based targets are not supported"
+# define PTRLOG 2
+# define SZREG 4
+# define REG_S sw
+# define REG_L lw
+// # warning "rv32i-based targets are experimental"
#else
# error __riscv_xlen must equal 32 or 64
#endif
--
2.37.1