Messages in this thread | | | From | Alexander Kuleshov <> | Subject | [PATCH v14 0/4] x86/earlyprintk: setup serial earlyprintk as early as possible | Date | Wed, 1 Jul 2015 15:42:40 +0600 |
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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 or in another words earlyprintk is usable only during early boot, kernel decompression and after call of the parse_early_param(). But there are many stuff after the kernel decompression and before the parse_early_param() will be called as memblock usage, early cpu initialization, early ioremap initialization and etc... So earlyprintk allows us to see what's going on there.
Changelog:
v14: * style and commit messages fixes; * earlyprintk_late renamed to is_earlyprintk_late
v13: * do not setup pciserial from the arch/x86/kernel/head{32,64}.c, because it uses ioremap and we can't do it really early; * style fixes; * patch for testing.
v12: * all changes from the v11 are reverted * setup_early_serial_console() renamed to the setup_earlyprintk_console() and refactored. Now it checks 'earlyprintk=' in the kernel command line, set earlyprintk_late variable to false. This variable allows to know, do we can setup early console for the certain device.
v11: * setup_log_buf moved to the arch/x86/kernel/head{32,64.c} from the arch/x86/kernel/setup.c to setup early log_buf for the earlyprintl * Update log_buf in the early_printk function * Added additional patch for testing earlyprintk
v10: * Removed style issues which are not related to the patchset.
v9: * Add call of the lockdep_init() to the arch/x86/kernel/head{32,64}.c before the serial console initialization to prevent:
[ 0.000000] WARNING: lockdep init error! lock-(console_sem).lock was acquiredbefore lockdep_init [ 0.000000] Call stack leading to lockdep invocation was: [ 0.000000] [] save_stack_trace+0x2f/0x50 [ 0.000000] [] __lock_acquire+0xa2c/0xf00 [ 0.000000] [] lock_acquire+0xdb/0x2b0 [ 0.000000] [] _raw_spin_lock_irqsave+0x53/0x90 [ 0.000000] [] down+0x16/0x50 [ 0.000000] [] console_lock+0x19/0x60 [ 0.000000] [] register_console+0x116/0x350 [ 0.000000] [] setup_early_printk+0x165/0x467 [ 0.000000] [] setup_early_serial_console+0x56/0x58 [ 0.000000] [] x86_64_start_kernel+0xce/0x110 [ 0.000000] [] 0xffffffffffffffff [ 0.000000] ------------------------
during early serial console initialization.
* Add additional check to the earlyprintk initialization to protect double initialization of the early_serial_console. * Fixed comment.
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 setup_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 (4): x86/setup: introduce setup_bultin_cmdline x86/setup: handle builtin command line as early as possible x86/earlyprintk: setup earlyprintk as early as possible x86/earlyprintk: add some early_printk for tests
arch/x86/include/asm/setup.h | 7 +++++++ arch/x86/kernel/early_printk.c | 42 +++++++++++++++++++++++++++++++++++------- arch/x86/kernel/head32.c | 5 +++++ arch/x86/kernel/head64.c | 7 +++++++ arch/x86/kernel/setup.c | 31 ++++++++++++++++++------------- init/main.c | 2 ++ 6 files changed, 74 insertions(+), 20 deletions(-)
-- 2.4.0.GIT
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