The early_printk function is usable only after the setup_early_printk will
be executed. We pass 'earlyprintk' through the kernel command line. So, it
means that earlyprintk will be usable only after the 'parse_early_param'
will be executed. We have usable earlyprintk only during early boot, kernel
decompression and after call of the 'parse_early_param'. This patchset makes
serial earlyprintk usable before the call of the 'parse_early_param'.
These patchset provides following changes:
1. Move handling of the builtin command line to the separate function
from the setup_arch. Now we can call it from the arch/x86/kernel/head{32,64}.c,
and find 'earlyprintk' kernel command line paramter there.
2. Provide setup_serial_console function to setup serial earlyprintk in the
arch/x86/kernel/head{32,64}.c
v7:
* Move setup_early_serial_console to the the arch/x86/include/setup.h
* Add ifdefs to prevent setup_serial_console if CONFIG_EARLY_PRINTK
is not set.
v6:
* Style fixes.
* Call of the suetp_builtin_cmdline moved to the separate patch.
v5:
* Call setup_builtin_cmdline instead of setup_cmdline
v4:
* Move setup_early_serial_console from the include/linux/printk.h
to the arch/x86/include/asm/serial.h, because this function is only
for x86 now.
v3:
* Call setup_cmdline before setup_early_printk;
* setup_early_printk call wrapped with the setup_early_serial_console which
checks that 'serial' given to the earlyprintk command line option. This
prevents call of the setup_early_printk with the given pciserial/dbgp/efi,
because they are using early_ioremap.
v2:
* Comment added before the setup_early_printk call;
* Added information about testing to the commit message.
Alexander Kuleshov (3):
x86/setup: introduce setup_bultin_cmdline
x86/setup: handle builtin command line as early as possible
x86/earlyprintk: setup earlyprintk as early as possible
arch/x86/include/asm/setup.h | 8 ++++++++
arch/x86/kernel/early_printk.c | 24 ++++++++++++++++++++++++
arch/x86/kernel/head32.c | 7 +++++++
arch/x86/kernel/head64.c | 7 +++++++
arch/x86/kernel/setup.c | 33 ++++++++++++++++++---------------
5 files changed, 64 insertions(+), 15 deletions(-)
--
2.4.0
This patch introduces the setup_builtin_cmdline function which appends or
overrides boot_command_line with the builtin_cmdline if CONFIG_CMDLINE_BOOL
is set.
Previously this functional was in the setup_arch, but we need to move
it for getting actual command line as early as possible in the
arch/x86/kernel/head{32,64}.c for the earlyprintk setup.
Signed-off-by: Alexander Kuleshov <[email protected]>
---
arch/x86/include/asm/setup.h | 1 +
arch/x86/kernel/setup.c | 30 +++++++++++++++++-------------
2 files changed, 18 insertions(+), 13 deletions(-)
diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index f69e06b..59efd0d 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -119,6 +119,7 @@ asmlinkage void __init x86_64_start_kernel(char *real_mode);
asmlinkage void __init x86_64_start_reservations(char *real_mode_data);
#endif /* __i386__ */
+void __init setup_builtin_cmdline(void);
#endif /* _SETUP */
#else
#define RESERVE_BRK(name,sz) \
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index d74ac33..edd4857 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -845,6 +845,22 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
return 0;
}
+void __init setup_builtin_cmdline(void)
+{
+#ifdef CONFIG_CMDLINE_BOOL
+#ifdef CONFIG_CMDLINE_OVERRIDE
+ strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+#else
+ if (builtin_cmdline[0]) {
+ /* append boot loader cmdline to builtin */
+ strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
+ strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
+ strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+ }
+#endif
+#endif
+}
+
/*
* Determine if we were loaded by an EFI loader. If so, then we have also been
* passed the efi memmap, systab, etc., so we should use these data structures
@@ -973,19 +989,7 @@ void __init setup_arch(char **cmdline_p)
bss_resource.start = __pa_symbol(__bss_start);
bss_resource.end = __pa_symbol(__bss_stop)-1;
-#ifdef CONFIG_CMDLINE_BOOL
-#ifdef CONFIG_CMDLINE_OVERRIDE
- strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
-#else
- if (builtin_cmdline[0]) {
- /* append boot loader cmdline to builtin */
- strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
- strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
- strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
- }
-#endif
-#endif
-
+ setup_builtin_cmdline();
strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
*cmdline_p = command_line;
--
2.4.0
This patch adds the call of the setup_builtin_cmdline to
handle builtin command line before we will setup earlyprintk.
Signed-off-by: Alexander Kuleshov <[email protected]>
---
arch/x86/kernel/head32.c | 1 +
arch/x86/kernel/head64.c | 2 ++
arch/x86/kernel/setup.c | 1 -
3 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index 2911ef3..92e8b5f 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -31,6 +31,7 @@ static void __init i386_default_early_setup(void)
asmlinkage __visible void __init i386_start_kernel(void)
{
+ setup_builtin_cmdline();
cr4_init_shadow();
sanitize_boot_params(&boot_params);
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 2b55ee6..346a042 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -172,6 +172,8 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
copy_bootdata(__va(real_mode_data));
+ setup_builtin_cmdline();
+
/*
* Load microcode early on BSP.
*/
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 28dea1c..12124df 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -989,8 +989,6 @@ void __init setup_arch(char **cmdline_p)
bss_resource.start = __pa_symbol(__bss_start);
bss_resource.end = __pa_symbol(__bss_stop)-1;
- setup_builtin_cmdline();
strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
*cmdline_p = command_line;
--
2.4.0
The early_printk function is usable only after the setup_early_printk will
be executed. We pass 'earlyprintk' through the kernel command line, so it
will be usable only after the 'parse_early_param' will be executed. This means
that we have usable earlyprintk only during early boot, kernel decompression
and after call of the 'parse_early_param'. This patchset makes earlyprintk
usable before the call of the 'parse_early_param'.
This patch makes the setup_early_printk visible for head{32,64}.c. So the
'early_printk' function will be usabable after decompression of the
kernel and before parse_early_param will be called. It also must be
safe if CONFIG_CMDLINE_BOOL and CONFIG_CMDLINE_OVERRIDE are set, because
setup_cmdline function will be called before setup_early_printk.
It provides earlyprintk only for serial console, because other needs in
ioremap which is not initialized yet.
Tested it with qemu, so early_printk() is usable and prints to serial
console right after setup_early_printk function called.
Signed-off-by: Alexander Kuleshov <[email protected]>
---
arch/x86/include/asm/setup.h | 7 +++++++
arch/x86/kernel/early_printk.c | 24 ++++++++++++++++++++++++
arch/x86/kernel/head32.c | 6 ++++++
arch/x86/kernel/head64.c | 5 +++++
4 files changed, 42 insertions(+)
diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index 59efd0d..4234ada 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -120,6 +120,13 @@ asmlinkage void __init x86_64_start_reservations(char *real_mode_data);
#endif /* __i386__ */
void __init setup_builtin_cmdline(void);
+#ifdef CONFIG_EARLY_PRINTK
+/* used by arch/x86/kernel/head{32,64}.c */
+int __init setup_early_serial_console(void);
+#else
+int __init setup_early_serial_console(void) { }
+#endif /* CONFIG_EARLY_PRINTK */
#endif /* _SETUP */
#else
#define RESERVE_BRK(name,sz) \
diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
index 89427d8..0b2a626 100644
--- a/arch/x86/kernel/early_printk.c
+++ b/arch/x86/kernel/early_printk.c
@@ -385,4 +385,28 @@ static int __init setup_early_printk(char *buf)
return 0;
}
+int __init setup_early_serial_console(void)
+{
+ char *arg;
+
+ /*
+ * make sure that we have:
+ * "serial,0x3f8,115200"
+ * "serial,ttyS0,115200"
+ * "ttyS0,115200"
+ */
+ arg = strstr(boot_command_line, "earlyprintk=serial");
+ if (!arg)
+ arg = strstr(boot_command_line, "earlyprintk=ttyS");
+ if (!arg)
+ return -1;
+
+ arg = strstr(boot_command_line, "earlyprintk=");
+
+ /* += strlen("earlyprintk"); */
+ arg += 12;
+
+ return setup_early_printk(arg);
+}
+
early_param("earlyprintk", setup_early_printk);
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index 92e8b5f..759d115 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -32,6 +32,12 @@ static void __init i386_default_early_setup(void)
asmlinkage __visible void __init i386_start_kernel(void)
{
setup_builtin_cmdline();
+
+ setup_early_serial_console();
+
+ if (console_loglevel >= CONSOLE_LOGLEVEL_DEBUG)
+ early_printk("Early printk is initialized\n");
+
cr4_init_shadow();
sanitize_boot_params(&boot_params);
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 346a042..6b7529a 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -174,7 +174,11 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data)
setup_builtin_cmdline();
+ setup_early_serial_console();
+
+ if (console_loglevel >= CONSOLE_LOGLEVEL_DEBUG)
+ early_printk("Early printk is initialized\n");
+
/*
* Load microcode early on BSP.
*/
--
2.4.0
The early_printk function is usable only after the setup_early_printk will
be executed. We pass 'earlyprintk' through the kernel command line. So, it
means that earlyprintk will be usable only after the 'parse_early_param'
will be executed. We have usable earlyprintk only during early boot, kernel
decompression and after call of the 'parse_early_param'. This patchset makes
serial earlyprintk usable before the call of the 'parse_early_param'.
Patchset was tested for both x86 and x86_64 architectures with the qemu.
These patchset provides following changes:
1. Move handling of the builtin command line to the separate function
from the setup_arch. Now we can call it from the arch/x86/kernel/head{32,64}.c,
and find 'earlyprintk' kernel command line paramter there.
2. Provide setup_serial_console function to setup serial earlyprintk in the
arch/x86/kernel/head{32,64}.c
v8:
* Fixed warning with the definition of the setup_early_serial_console
in the arch/x86/include/asm/setup.h
v7:
* Move setup_early_serial_console to the the arch/x86/include/setup.h
* Add ifdefs to prevent setup_serial_console if CONFIG_EARLY_PRINTK
is not set.
v6:
* Style fixes.
* Call of the suetp_builtin_cmdline moved to the separate patch.
v5:
* Call setup_builtin_cmdline instead of setup_cmdline
v4:
* Move setup_early_serial_console from the include/linux/printk.h
to the arch/x86/include/asm/serial.h, because this function is only
for x86 now.
v3:
* Call setup_cmdline before setup_early_printk;
* setup_early_printk call wrapped with the setup_early_serial_console which
checks that 'serial' given to the earlyprintk command line option. This
prevents call of the setup_early_printk with the given pciserial/dbgp/efi,
because they are using early_ioremap.
v2:
* Comment added before the setup_early_printk call;
* Added information about testing to the commit message.
Alexander Kuleshov (3):
x86/setup: introduce setup_bultin_cmdline
x86/setup: handle builtin command line as early as possible
x86/earlyprintk: setup earlyprintk as early as possible
arch/x86/include/asm/setup.h | 8 ++++++++
arch/x86/kernel/early_printk.c | 24 ++++++++++++++++++++++++
arch/x86/kernel/head32.c | 7 +++++++
arch/x86/kernel/head64.c | 7 +++++++
arch/x86/kernel/setup.c | 33 ++++++++++++++++++---------------
5 files changed, 64 insertions(+), 15 deletions(-)
--
2.4.0.350.g9532ead