diff mbox series

[uclibc-ng-devel] RISC-V 32-bit support

Message ID 166886657534.1337.4069952366679464194@helium.openadk.org
State Accepted
Headers show
Series [uclibc-ng-devel] RISC-V 32-bit support | expand

Commit Message

Yimin Gu Nov. 19, 2022, 2:02 p.m. UTC 
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@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

Comments

Waldemar Brodkorb Nov. 20, 2022, 7:46 a.m. UTC | #1 
Hi Yimin,

applied and pushed,
thx
 Waldemar

ustcymgu@gmail.com wrote,

> 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.
diff mbox series

Patch

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