Messages in this thread Patch in this message |  | | Date | Mon, 8 Jun 2015 11:33:26 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH v10 3/3] x86/earlyprintk: setup earlyprintk as early as possible |
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On Sun, Jun 07, 2015 at 08:14:37PM +0600, Alexander Kuleshov wrote: > 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 <kuleshovmail@gmail.com> > --- > arch/x86/include/asm/setup.h | 7 +++++++ > arch/x86/kernel/early_printk.c | 30 ++++++++++++++++++++++++++++-- > arch/x86/kernel/head32.c | 7 +++++++ > arch/x86/kernel/head64.c | 6 ++++++ > 4 files changed, 48 insertions(+), 2 deletions(-)
...
> diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c > index 92e8b5f..6969d97 100644 > --- a/arch/x86/kernel/head32.c > +++ b/arch/x86/kernel/head32.c > @@ -32,6 +32,13 @@ static void __init i386_default_early_setup(void) > asmlinkage __visible void __init i386_start_kernel(void) > { > setup_builtin_cmdline(); > + > + lockdep_init(); > + > + setup_early_serial_console(); > + > + 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 1e5f064..769d411 100644 > --- a/arch/x86/kernel/head64.c > +++ b/arch/x86/kernel/head64.c > @@ -174,7 +174,12 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) > > setup_builtin_cmdline(); > > + lockdep_init();
So you've added that lockdep_init() call here and above on the 32-bit path and haven't removed the one in start_kernel().
* Then, your patches don't apply. Something garbles them insanely so that not even fuzzy, ignore-context patch --merge works. Please fix your setup. For that, send your patches to yourself and try applying them. Send them out only if they apply cleanly.
And do them against tip/master or latest Linus rc, alternatively.
* To that patchset: I did the diff below ontop of yours to check whether that early printk actually works.
And it doesn't on my test box here.
The beginning of my dmesg contains:
[ 0.000000] bootconsole [earlyser0] enabled [ 0.000000] Initializing cgroup subsys cpuset [ 0.000000] Initializing cgroup subsys cpu [ 0.000000] Initializing cgroup subsys cpuacct [ 0.000000] Linux version 4.1.0-rc6+ (root@gondor) (gcc version 4.9.1 (Debian 4.9.1-19) ) #2 SMP PREEMPT Mon Jun 8 11:10:00 CEST 2015 [ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.1.0-rc6+ root=/dev/sda7 ro earlyprintk=ttyS0,115200 console=ttyS0,115200 console=tty0 root=/dev/sda7 log_buf_len=10M resume=/dev/sda5 no_console_suspend ignore_loglevel [ 0.000000] KERNEL supported cpus: [ 0.000000] Intel GenuineIntel [ 0.000000] AMD AuthenticAMD [ 0.000000] Centaur CentaurHauls [ 0.000000] x86/fpu: xstate_offset[2]: 0240, xstate_sizes[2]: 0100 [ 0.000000] x86/fpu: Supporting XSAVE feature 0x01: 'x87 floating point registers' [ 0.000000] x86/fpu: Supporting XSAVE feature 0x02: 'SSE registers' [ 0.000000] x86/fpu: Supporting XSAVE feature 0x04: 'AVX registers' [ 0.000000] x86/fpu: Enabled xstate features 0x7, context size is 0x340 bytes, using 'standard' format. [ 0.000000] x86/fpu: Using 'eager' FPU context switches. [ 0.000000] e820: BIOS-provided physical RAM map: ...
and I have CONFIG_EARLY_PRINTK=y. So provided I'm not missing anything, I'd say you'd need to do more staring.
So I'd suggest you test your patches on bare metal, both 32-bit and 64-bit with a similar diff as the one I've done below.
HTH.
--- diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index d4ea6ec28f09..20dd514ce838 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -179,7 +179,6 @@ asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) early_printk("Early printk is initialized\n"); - /* * Load microcode early on BSP. */ @@ -202,5 +201,7 @@ void __init x86_64_start_reservations(char *real_mode_data) reserve_ebda_region(); + early_printk("Will start_kernel\n"); + start_kernel(); } diff --git a/init/main.c b/init/main.c index 2115055faeac..e9180445283e 100644 --- a/init/main.c +++ b/init/main.c @@ -494,6 +494,8 @@ asmlinkage __visible void __init start_kernel(void) char *command_line; char *after_dashes; + early_printk("Will run lockdep_init needlessly one more time\n"); + /* * Need to run as early as possible, to initialize the * lockdep hash: @@ -530,6 +532,8 @@ asmlinkage __visible void __init start_kernel(void) build_all_zonelists(NULL, NULL); page_alloc_init(); + early_printk("Early Kernel command line: %s\n", boot_command_line); + pr_notice("Kernel command line: %s\n", boot_command_line); parse_early_param(); after_dashes = parse_args("Booting kernel",
-- Regards/Gruss, Boris.
ECO tip #101: Trim your mails when you reply. --
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