The following patch series implements support for the early
console on the RISC-V platform.
Jinglin Wen (3):
riscv: Support for early console.
riscv: Support SBI as the interface for the RISC-V early console
riscv: Add information for MAINTAINERS
MAINTAINERS | 6 ++
arch/riscv/include/asm/early_console.h | 23 ++++++
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/early_console.c | 108 +++++++++++++++++++++++++
arch/riscv/kernel/setup.c | 2 +
drivers/tty/hvc/Kconfig | 12 +++
drivers/tty/hvc/hvc_riscv_sbi.c | 29 +++++++
7 files changed, 181 insertions(+)
create mode 100644 arch/riscv/include/asm/early_console.h
create mode 100644 arch/riscv/kernel/early_console.c
--
2.25.1
This feature is mainly used for debugging during the early startup
process. Currently, the implementation of this function is based
on the sbi interface.
By setting the CONFIG_RISCV_EARLY_CONSOLE option, this
function can be enabled, which subsequently sets the log level
to CONSOLE_LOGLEVEL_MOTORMOUT.
Signed-off-by: Jinglin Wen <[email protected]>
---
arch/riscv/include/asm/early_console.h | 23 ++++++
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/early_console.c | 108 +++++++++++++++++++++++++
arch/riscv/kernel/setup.c | 2 +
4 files changed, 134 insertions(+)
create mode 100644 arch/riscv/include/asm/early_console.h
create mode 100644 arch/riscv/kernel/early_console.c
diff --git a/arch/riscv/include/asm/early_console.h b/arch/riscv/include/asm/early_console.h
new file mode 100644
index 000000000000..0683a42e9207
--- /dev/null
+++ b/arch/riscv/include/asm/early_console.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _ASM_EARLY_CONSOLE_H
+#define _ASM_EARLY_CONSOLE_H
+#ifdef __KERNEL__
+
+#include <linux/compiler.h>
+#include <linux/init.h>
+
+void __init early_console_init(void);
+
+/* early_console libs */
+void early_console_puts(const char *s);
+int early_console_write(const char *s, int n);
+void early_console_printf(const char *fmt, ...);
+void early_console_progress(char *s, unsigned short hex);
+
+#ifdef CONFIG_RISCV_EARLY_CONSOLE_SBI
+void __init hvc_sbi_early_init(void (**putc)(char c));
+#endif /* CONFIG_HVC_RISCV_SBI */
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_EARLY_CONSOLE_H */
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 81d94a8ee10f..ef037e3762f1 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -48,6 +48,7 @@ obj-y += ptrace.o
obj-y += reset.o
obj-y += return_address.o
obj-y += setup.o
+obj-y += early_console.o
obj-y += signal.o
obj-y += syscall_table.o
obj-y += sys_riscv.o
diff --git a/arch/riscv/kernel/early_console.c b/arch/riscv/kernel/early_console.c
new file mode 100644
index 000000000000..64f3a5705413
--- /dev/null
+++ b/arch/riscv/kernel/early_console.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Early console support for RISCV
+ */
+
+#include <linux/stdarg.h>
+#include <linux/types.h>
+#include <linux/console.h>
+#include <asm/sbi.h>
+#include <asm/early_console.h>
+
+/* interface for early console output characters */
+void (*riscv_early_console_putc)(char c);
+
+void early_console_puts(const char *s)
+{
+ if (riscv_early_console_putc) {
+ char c;
+
+ if (s && *s != '\0') {
+ while ((c = *s++) != '\0')
+ riscv_early_console_putc(c);
+ }
+ }
+}
+
+int early_console_write(const char *s, int n)
+{
+ int remain = n;
+ char c;
+
+ if (!riscv_early_console_putc)
+ return 0;
+
+ if (s && *s != '\0') {
+ while (((c = *s++) != '\0') && (remain-- > 0))
+ riscv_early_console_putc(c);
+ }
+
+ return n - remain;
+}
+
+#define EARLY_CONSOLE_BUFSIZE 256
+void early_console_printf(const char *fmt, ...)
+{
+ if (riscv_early_console_putc) {
+ char buf[EARLY_CONSOLE_BUFSIZE];
+ va_list args;
+
+ va_start(args, fmt);
+ vsnprintf(buf, EARLY_CONSOLE_BUFSIZE, fmt, args);
+ early_console_puts(buf);
+ va_end(args);
+ }
+}
+
+void __init early_console_progress(char *s, unsigned short hex)
+{
+ early_console_puts(s);
+ early_console_puts("\n");
+}
+
+/*
+ * Console based on early console
+ */
+static void riscv_early_console_write(struct console *con, const char *s,
+ unsigned int n)
+{
+ early_console_write(s, n);
+}
+
+static struct console riscv_early_console = {
+ .name = "riscv_early_con",
+ .write = riscv_early_console_write,
+ .flags = CON_PRINTBUFFER | CON_ENABLED | CON_BOOT | CON_ANYTIME,
+ .index = 0,
+};
+
+static void __init register_early_console(void)
+{
+ if (!riscv_early_console_putc)
+ return;
+
+ add_preferred_console("riscv_early_con", 0, NULL);
+ register_console(&riscv_early_console);
+}
+
+/*
+ * This is called after sbi_init.
+ */
+void __init early_console_init(void)
+{
+ /*
+ * Set riscv_early_console_putc.
+ * If there are other output interfaces, you can add corresponding code
+ * to initialize riscv_early_console_putc.
+ */
+#if defined(CONFIG_RISCV_EARLY_CONSOLE_SBI)
+ /* using the sbi */
+ hvc_sbi_early_init(&riscv_early_console_putc);
+#else
+ /* using other */
+#endif
+
+ console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
+ register_early_console();
+}
+
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 4f73c0ae44b2..1b48630f0861 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -36,6 +36,7 @@
#include <asm/thread_info.h>
#include <asm/kasan.h>
#include <asm/efi.h>
+#include <asm/early_console.h>
#include "head.h"
@@ -255,6 +256,7 @@ void __init setup_arch(char **cmdline_p)
early_ioremap_setup();
sbi_init();
+ early_console_init();
jump_label_init();
parse_early_param();
--
2.25.1
Use the SBI interface as the early console output interface
for the RISC-V platform.
Signed-off-by: Jinglin Wen <[email protected]>
---
drivers/tty/hvc/Kconfig | 12 ++++++++++++
drivers/tty/hvc/hvc_riscv_sbi.c | 29 +++++++++++++++++++++++++++++
2 files changed, 41 insertions(+)
diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig
index c2a4e88b328f..48658d2b700c 100644
--- a/drivers/tty/hvc/Kconfig
+++ b/drivers/tty/hvc/Kconfig
@@ -118,6 +118,18 @@ config HVC_RISCV_SBI
If you don't know what do to here, say N.
+config RISCV_EARLY_CONSOLE_SBI
+ bool "Use SBI as the interface for RISC-V early console"
+ depends on RISCV
+ help
+ Choose 'Y' to use the SBI interface as the early console
+ output interface for the RISC-V platform.
+
+ This configuration is a temporary setup for debugging
+ purposes during the boot process to address issues as
+ early as possible. It should not be enabled in production
+ kernel.
+
config HVCS
tristate "IBM Hypervisor Virtual Console Server support"
depends on PPC_PSERIES && HVC_CONSOLE
diff --git a/drivers/tty/hvc/hvc_riscv_sbi.c b/drivers/tty/hvc/hvc_riscv_sbi.c
index cede8a572594..6686dcf62853 100644
--- a/drivers/tty/hvc/hvc_riscv_sbi.c
+++ b/drivers/tty/hvc/hvc_riscv_sbi.c
@@ -12,6 +12,7 @@
#include <linux/types.h>
#include <asm/sbi.h>
+#include <asm/early_console.h>
#include "hvc_console.h"
@@ -81,3 +82,31 @@ static int __init hvc_sbi_init(void)
return 0;
}
device_initcall(hvc_sbi_init);
+
+#ifdef CONFIG_RISCV_EARLY_CONSOLE_SBI
+static ssize_t (*sbi_early_putc_common)(uint32_t vtermno, const u8 *buf, size_t count);
+
+static void sbi_early_putc(char c)
+{
+ unsigned int termno = 0;
+ int count = -1;
+
+ if (c == '\n')
+ sbi_early_putc('\r');
+
+ do {
+ count = sbi_early_putc_common(termno, &c, 1);
+ } while (count == 0 || count == -EAGAIN);
+}
+
+void __init hvc_sbi_early_init(void (**putc)(char c))
+{
+ if (sbi_debug_console_available)
+ sbi_early_putc_common = hvc_sbi_dbcn_tty_put;
+ else if (IS_ENABLED(CONFIG_RISCV_SBI_V01))
+ sbi_early_putc_common = hvc_sbi_tty_put;
+
+ if (sbi_early_putc_common)
+ *putc = sbi_early_putc;
+}
+#endif
--
2.25.1
Add the description of the RISC-V early console to
MAINTAINERS.
Signed-off-by: Jinglin Wen <[email protected]>
---
MAINTAINERS | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index aa3b947fb080..bdc013ac4e75 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18936,6 +18936,12 @@ F: arch/riscv/
N: riscv
K: riscv
+RISC-V EARLY CONSOLE SUPPORT
+M: Jinglin Wen <[email protected]>
+S: Supported
+F: arch/riscv/include/asm/early_console.h
+F: arch/riscv/kernel/early_console.c
+
RISC-V MICROCHIP FPGA SUPPORT
M: Conor Dooley <[email protected]>
M: Daire McNamara <[email protected]>
--
2.25.1
Jinglin Wen <[email protected]> writes:
> The following patch series implements support for the early
> console on the RISC-V platform.
I fail to see how this is different from earlycon=sbi?
Björn
Thank you for taking the time to review this patch.
Björn <[email protected]> writes:
> Jinglin Wen <[email protected]> writes:
>
> > The following patch series implements support for the early
> > console on the RISC-V platform.
>
> I fail to see how this is different from earlycon=3Dsbi
Yep, you are right, this patch duplicates the functionality of
earlycon=sbi, and should be discarded.
Thanks,
Jinglin Wen
Hi Jinglin,
kernel test robot noticed the following build warnings:
[auto build test WARNING on tty/tty-testing]
[also build test WARNING on tty/tty-next tty/tty-linus linus/master v6.9-rc3 next-20240410]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Jinglin-Wen/riscv-Support-for-early-console/20240410-143840
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
patch link: https://lore.kernel.org/r/20240410063432.23058-2-jinglin.wen%40shingroup.cn
patch subject: [PATCH 1/3] riscv: Support for early console.
config: riscv-allnoconfig (https://download.01.org/0day-ci/archive/20240411/[email protected]/config)
compiler: riscv64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240411/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All warnings (new ones prefixed by >>):
arch/riscv/kernel/early_console.c: In function 'early_console_printf':
>> arch/riscv/kernel/early_console.c:51:17: warning: function 'early_console_printf' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
51 | vsnprintf(buf, EARLY_CONSOLE_BUFSIZE, fmt, args);
| ^~~~~~~~~
vim +51 arch/riscv/kernel/early_console.c
42
43 #define EARLY_CONSOLE_BUFSIZE 256
44 void early_console_printf(const char *fmt, ...)
45 {
46 if (riscv_early_console_putc) {
47 char buf[EARLY_CONSOLE_BUFSIZE];
48 va_list args;
49
50 va_start(args, fmt);
> 51 vsnprintf(buf, EARLY_CONSOLE_BUFSIZE, fmt, args);
52 early_console_puts(buf);
53 va_end(args);
54 }
55 }
56
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Thank you for taking the time to review this patch.
Bjorn <[email protected]> writes:
> Jinglin Wen <[email protected]> writes:
>
> > The following patch series implements support for the early
> > console on the RISC-V platform.
>
> I fail to see how this is different from earlycon=3Dsbi
Yep, you are right, this patch duplicates the functionality of
earlycon=sbi, and should be discarded.
Thanks,
Jinglin Wen
Hi Jinglin,
kernel test robot noticed the following build warnings:
[auto build test WARNING on tty/tty-testing]
[also build test WARNING on tty/tty-next tty/tty-linus linus/master v6.9-rc3 next-20240410]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Jinglin-Wen/riscv-Support-for-early-console/20240410-143840
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
patch link: https://lore.kernel.org/r/20240410063432.23058-2-jinglin.wen%40shingroup.cn
patch subject: [PATCH 1/3] riscv: Support for early console.
config: riscv-randconfig-r112-20240411 (https://download.01.org/0day-ci/archive/20240411/[email protected]/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 8b3b4a92adee40483c27f26c478a384cd69c6f05)
reproduce: (https://download.01.org/0day-ci/archive/20240411/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
sparse warnings: (new ones prefixed by >>)
>> arch/riscv/kernel/early_console.c:13:6: sparse: sparse: symbol 'riscv_early_console_putc' was not declared. Should it be static?
vim +/riscv_early_console_putc +13 arch/riscv/kernel/early_console.c
11
12 /* interface for early console output characters */
> 13 void (*riscv_early_console_putc)(char c);
14
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Jinglin,
kernel test robot noticed the following build errors:
[auto build test ERROR on tty/tty-testing]
[also build test ERROR on tty/tty-next tty/tty-linus linus/master v6.9-rc4 next-20240416]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Jinglin-Wen/riscv-Support-for-early-console/20240410-143840
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
patch link: https://lore.kernel.org/r/20240410063432.23058-3-jinglin.wen%40shingroup.cn
patch subject: [PATCH 2/3] riscv: SBI as the interface for the early console
config: riscv-randconfig-r071-20240417 (https://download.01.org/0day-ci/archive/20240417/[email protected]/config)
compiler: riscv64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240417/[email protected]/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All errors (new ones prefixed by >>):
riscv64-linux-ld: arch/riscv/kernel/early_console.o: in function `early_console_init':
>> arch/riscv/kernel/early_console.c:100:(.init.text+0x18): undefined reference to `hvc_sbi_early_init'
vim +100 arch/riscv/kernel/early_console.c
f4e6608ec4adae Jinglin Wen 2024-04-10 87
f4e6608ec4adae Jinglin Wen 2024-04-10 88 /*
f4e6608ec4adae Jinglin Wen 2024-04-10 89 * This is called after sbi_init.
f4e6608ec4adae Jinglin Wen 2024-04-10 90 */
f4e6608ec4adae Jinglin Wen 2024-04-10 91 void __init early_console_init(void)
f4e6608ec4adae Jinglin Wen 2024-04-10 92 {
f4e6608ec4adae Jinglin Wen 2024-04-10 93 /*
f4e6608ec4adae Jinglin Wen 2024-04-10 94 * Set riscv_early_console_putc.
f4e6608ec4adae Jinglin Wen 2024-04-10 95 * If there are other output interfaces, you can add corresponding code
f4e6608ec4adae Jinglin Wen 2024-04-10 96 * to initialize riscv_early_console_putc.
f4e6608ec4adae Jinglin Wen 2024-04-10 97 */
f4e6608ec4adae Jinglin Wen 2024-04-10 98 #if defined(CONFIG_RISCV_EARLY_CONSOLE_SBI)
f4e6608ec4adae Jinglin Wen 2024-04-10 99 /* using the sbi */
f4e6608ec4adae Jinglin Wen 2024-04-10 @100 hvc_sbi_early_init(&riscv_early_console_putc);
f4e6608ec4adae Jinglin Wen 2024-04-10 101 #else
f4e6608ec4adae Jinglin Wen 2024-04-10 102 /* using other */
f4e6608ec4adae Jinglin Wen 2024-04-10 103 #endif
f4e6608ec4adae Jinglin Wen 2024-04-10 104
f4e6608ec4adae Jinglin Wen 2024-04-10 105 console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
f4e6608ec4adae Jinglin Wen 2024-04-10 106 register_early_console();
f4e6608ec4adae Jinglin Wen 2024-04-10 107 }
f4e6608ec4adae Jinglin Wen 2024-04-10 108
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki