mirror of https://github.com/hak5/openwrt.git
265 lines
8.1 KiB
Diff
265 lines
8.1 KiB
Diff
From 8e18a9db5f895f654b06000d7bd10528e6b795f3 Mon Sep 17 00:00:00 2001
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From: Andy Green <andy@openmoko.com>
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Date: Wed, 2 Jul 2008 22:44:11 +0100
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Subject: [PATCH] introduce-resume-exception-capture.patch
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This patch introduces a new resume debugging concept: if we
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get an OOPS inbetween starting suspend and finishing resume, it
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uses a new "emergency spew" device similar to BUT NOT REQUIRING
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CONFIG_DEBUG_LL to dump the syslog buffer and then the OOPS
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on the debug device defined by the existing CONFIG_DEBUG_S3C_UART
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index. But neither CONFIG_DEBUG_LL nor the S3C low level configs
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are needed to use this feature.
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Another difference between this feature and CONFIG_DEBUG_LL is that
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it does not affect resume timing, ordering or UART traffic UNLESS
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there is an OOPS during resume.
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The patch adds three global exports, one to say if we are inside
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suspend / resume, and two callbacks for printk() to use to init
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and dump the emergency data. The callbacks are set in s3c serial
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device init, but the whole structure is arch independent.
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Signed-off-by: Andy Green <andy@openmoko.com>
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---
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drivers/serial/s3c2410.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++
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include/linux/kernel.h | 2 +
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include/linux/suspend.h | 6 ++++
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kernel/power/main.c | 10 ++++++-
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kernel/printk.c | 41 +++++++++++++++++++++++++++
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5 files changed, 127 insertions(+), 1 deletions(-)
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diff --git a/drivers/serial/s3c2410.c b/drivers/serial/s3c2410.c
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index 73c6284..fef3c8f 100644
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--- a/drivers/serial/s3c2410.c
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+++ b/drivers/serial/s3c2410.c
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@@ -81,6 +81,7 @@
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#include <asm/plat-s3c/regs-serial.h>
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#include <asm/arch/regs-gpio.h>
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+#include <asm/arch/regs-clock.h>
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/* structures */
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@@ -992,6 +993,69 @@ static struct s3c24xx_uart_port s3c24xx_serial_ports[NR_PORTS] = {
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#endif
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};
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+static void s3c24xx_serial_force_debug_port_up(void)
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+{
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+ struct s3c24xx_uart_port *ourport = &s3c24xx_serial_ports[
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+ CONFIG_DEBUG_S3C_UART];
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+ struct s3c24xx_uart_clksrc *clksrc = NULL;
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+ struct clk *clk = NULL;
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+ unsigned long tmp;
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+
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+ s3c24xx_serial_getclk(&ourport->port, &clksrc, &clk, 115200);
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+
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+ tmp = __raw_readl(S3C2410_CLKCON);
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+
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+ /* re-start uart clocks */
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+ tmp |= S3C2410_CLKCON_UART0;
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+ tmp |= S3C2410_CLKCON_UART1;
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+ tmp |= S3C2410_CLKCON_UART2;
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+
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+ __raw_writel(tmp, S3C2410_CLKCON);
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+ udelay(10);
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+
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+ s3c24xx_serial_setsource(&ourport->port, clksrc);
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+
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+ if (ourport->baudclk != NULL && !IS_ERR(ourport->baudclk)) {
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+ clk_disable(ourport->baudclk);
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+ ourport->baudclk = NULL;
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+ }
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+
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+ clk_enable(clk);
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+
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+ ourport->clksrc = clksrc;
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+ ourport->baudclk = clk;
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+}
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+
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+static void s3c2410_printascii(const char *sz)
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+{
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+ struct s3c24xx_uart_port *ourport = &s3c24xx_serial_ports[
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+ CONFIG_DEBUG_S3C_UART];
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+ struct uart_port *port = &ourport->port;
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+
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+ /* 8 N 1 */
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+ wr_regl(port, S3C2410_ULCON, (rd_regl(port, S3C2410_ULCON)) | 3);
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+ /* polling mode */
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+ wr_regl(port, S3C2410_UCON, (rd_regl(port, S3C2410_UCON) & ~0xc0f) | 5);
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+ /* disable FIFO */
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+ wr_regl(port, S3C2410_UFCON, (rd_regl(port, S3C2410_UFCON) & ~0x01));
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+ /* fix baud rate */
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+ wr_regl(port, S3C2410_UBRDIV, 26);
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+
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+ while (*sz) {
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+ int timeout = 10000000;
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+
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+ /* spin on it being busy */
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+ while ((!(rd_regl(port, S3C2410_UTRSTAT) & 2)) && timeout--)
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+ ;
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+
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+ /* transmit register */
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+ wr_regl(port, S3C2410_UTXH, *sz);
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+
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+ sz++;
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+ }
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+}
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+
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+
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/* s3c24xx_serial_resetport
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*
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* wrapper to call the specific reset for this port (reset the fifos
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@@ -1167,6 +1231,11 @@ static int s3c24xx_serial_resume(struct platform_device *dev)
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static int s3c24xx_serial_init(struct platform_driver *drv,
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struct s3c24xx_uart_info *info)
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{
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+ /* set up the emergency debug UART functions */
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+
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+ printk_emergency_debug_spew_init = s3c24xx_serial_force_debug_port_up;
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+ printk_emergency_debug_spew_send_string = s3c2410_printascii;
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+
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dbg("s3c24xx_serial_init(%p,%p)\n", drv, info);
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return platform_driver_register(drv);
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}
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diff --git a/include/linux/kernel.h b/include/linux/kernel.h
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index 94bc996..8e565b4 100644
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--- a/include/linux/kernel.h
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+++ b/include/linux/kernel.h
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@@ -182,6 +182,8 @@ asmlinkage int printk(const char * fmt, ...)
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extern int log_buf_get_len(void);
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extern int log_buf_read(int idx);
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extern int log_buf_copy(char *dest, int idx, int len);
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+extern void (*printk_emergency_debug_spew_init)(void);
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+extern void (*printk_emergency_debug_spew_send_string)(const char *);
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#else
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static inline int vprintk(const char *s, va_list args)
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__attribute__ ((format (printf, 1, 0)));
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diff --git a/include/linux/suspend.h b/include/linux/suspend.h
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index 4360e08..7186eef 100644
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--- a/include/linux/suspend.h
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+++ b/include/linux/suspend.h
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@@ -122,6 +122,12 @@ struct pbe {
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struct pbe *next;
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};
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+/**
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+ * global indication we are somewhere between start of suspend and end of
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+ * resume, nonzero is true
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+ */
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+extern int global_inside_suspend;
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+
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/* mm/page_alloc.c */
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extern void drain_local_pages(void);
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extern void mark_free_pages(struct zone *zone);
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diff --git a/kernel/power/main.c b/kernel/power/main.c
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index f71c950..d87bf0d 100644
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--- a/kernel/power/main.c
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+++ b/kernel/power/main.c
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@@ -31,6 +31,10 @@ DEFINE_MUTEX(pm_mutex);
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unsigned int pm_flags;
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EXPORT_SYMBOL(pm_flags);
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+int global_inside_suspend;
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+EXPORT_SYMBOL(global_inside_suspend);
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+
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+
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#ifdef CONFIG_SUSPEND
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/* This is just an arbitrary number */
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@@ -156,10 +160,12 @@ int suspend_devices_and_enter(suspend_state_t state)
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if (!suspend_ops)
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return -ENOSYS;
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+ global_inside_suspend = 1;
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+
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if (suspend_ops->set_target) {
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error = suspend_ops->set_target(state);
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if (error)
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- return error;
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+ goto bail;
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}
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suspend_console();
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error = device_suspend(PMSG_SUSPEND);
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@@ -183,6 +189,8 @@ int suspend_devices_and_enter(suspend_state_t state)
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device_resume();
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Resume_console:
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resume_console();
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+bail:
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+ global_inside_suspend = 0;
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return error;
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}
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diff --git a/kernel/printk.c b/kernel/printk.c
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index 89011bf..c8691bc 100644
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--- a/kernel/printk.c
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+++ b/kernel/printk.c
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@@ -33,8 +33,11 @@
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#include <linux/bootmem.h>
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#include <linux/syscalls.h>
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#include <linux/jiffies.h>
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+#include <linux/suspend.h>
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#include <asm/uaccess.h>
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+#include <asm/plat-s3c24xx/neo1973.h>
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+#include <asm/arch/gta02.h>
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#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
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@@ -61,6 +64,12 @@ int console_printk[4] = {
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int oops_in_progress;
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EXPORT_SYMBOL(oops_in_progress);
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+void (*printk_emergency_debug_spew_init)(void) = NULL;
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+EXPORT_SYMBOL(printk_emergency_debug_spew_init);
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+
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+void (*printk_emergency_debug_spew_send_string)(const char *) = NULL;
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+EXPORT_SYMBOL(printk_emergency_debug_spew_send_string);
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+
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/*
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* console_sem protects the console_drivers list, and also
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* provides serialisation for access to the entire console
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@@ -653,6 +662,38 @@ asmlinkage int vprintk(const char *fmt, va_list args)
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/* Emit the output into the temporary buffer */
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printed_len = vscnprintf(printk_buf, sizeof(printk_buf), fmt, args);
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+ /* if you're debugging resume, the normal methods can change resume
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+ * ordering behaviours because their debugging output is synchronous
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+ * (ie, CONFIG_DEBUG_LL). If your problem is an OOPS, this code
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+ * will not affect the speed and duration and ordering of resume
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+ * actions, but will give you a chance to read the full undumped
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+ * syslog AND the OOPS data when it happens
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+ *
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+ * if you support it, your debug device init can override the exported
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+ * emergency_debug_spew_init and emergency_debug_spew_send_string to
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+ * usually force polling or bitbanging on your debug console device
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+ */
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+ if (oops_in_progress && global_inside_suspend &&
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+ printk_emergency_debug_spew_init &&
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+ printk_emergency_debug_spew_send_string) {
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+ unsigned long cur_index;
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+ char ch[2];
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+
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+ if (global_inside_suspend == 1) {
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+ (printk_emergency_debug_spew_init)();
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+
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+ ch[1] = '\0';
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+ cur_index = con_start;
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+ while (cur_index != log_end) {
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+ ch[0] = LOG_BUF(cur_index);
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+ (printk_emergency_debug_spew_send_string)(ch);
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+ cur_index++;
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+ }
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+ global_inside_suspend++; /* only once */
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+ }
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+ (printk_emergency_debug_spew_send_string)(printk_buf);
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+ }
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+
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/*
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* Copy the output into log_buf. If the caller didn't provide
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* appropriate log level tags, we insert them here
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--
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1.5.6.5
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