On 2017/3/17 22:25, Dave Anderson wrote:
>
> ----- Original Message -----
>> However, that is why I am interested in your live system initialization
>> of kimage_voffset -- for live system access using /dev/mem, /proc/kcore,
>> or an older version of the /dev/crash driver that did not have the ioctl()
>> to read kimage_voffset. But, in order to do that, arm64_calc_kimage_voffset()
>> needs to be able to handle all /proc/iomem cases to correctly calculate
>> PHYS_OFFSET.
> Or better stated, your arm64_calc_kimage_voffset() needs to be able to handle all
> /proc/iomem cases to correctly calculate kimage_voffset. Because on the 4.8
> kernel, it does not work.
>
> Dave
>
> --
> Crash-utility mailing list
> Crash-utility@xxxxxxxxxx
> https://www.redhat.com/mailman/listinfo/crash-utility
Dave,
Sorry for my misunderstanding of PHYS_OFFSET, actually kimage_voffset
is the offset between kernel virtual address and physical address. So,
to calculate it need find out which physical address is mapping to
VA_START, not PHYS_OFFSET.
Please check patch v5, it should be OK for live system.
Thanks,
Yueyi
From e25004764456e20d8121f9ccc105fb7d408f1948 Mon Sep 17 00:00:00 2001
From: Yueyi Li <liyueyi@xxxxxxxx>
Date: Tue, 14 Mar 2017 21:25:21 +0800
Subject: [PATCH] [ARM64][patch] Auto calculate kimage_voffset by kaslr offset
ARM64 kimage_voffset can be calculated if kernel ASLR offset is known.
Add a function to auto calculate kimage_voffset when '--kaslr=<offset>'
was set.
---
arm64.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 82 insertions(+)
diff --git a/arm64.c b/arm64.c
index 6eaf96d..01e43e5 100644
--- a/arm64.c
+++ b/arm64.c
@@ -27,6 +27,7 @@
static struct machine_specific arm64_machine_specific = { 0 };
static int arm64_verify_symbol(const char *, ulong, char);
static void arm64_parse_cmdline_args(void);
+static void arm64_calc_kimage_voffset(void);
static void arm64_calc_phys_offset(void);
static void arm64_calc_virtual_memory_ranges(void);
static int arm64_kdump_phys_base(ulong *);
@@ -324,6 +325,9 @@ arm64_init(int when)
machdep->init_kernel_pgd = arm64_init_kernel_pgd;
/* use machdep parameters */
+ arm64_calc_kimage_voffset();
+
+ /* use machdep parameters */
arm64_calc_phys_offset();
if (CRASHDEBUG(1)) {
@@ -735,6 +739,83 @@ arm64_parse_cmdline_args(void)
}
}
+static void
+arm64_calc_kimage_voffset(void)
+{
+ struct machine_specific *ms = machdep->machspec;
+ ulong offset;
+
+ if (ms->kimage_voffset) /* vmcoreinfo or --machdep override */
+ return;
+
+ if (!(kt->flags2 & KASLR) || !(kt->flags & RELOC_SET)) /*Calculate kiamge_voffset when KASLR enabled.*/
+ return;
+
+ if(ACTIVE()){
+ char buf[BUFSIZE];
+ char *p1;
+ int errflag;
+ FILE *iomem;
+ ulong kernel_code_range;
+ ulong memory_end;
+ ulong memory_start;
+
+ if ((iomem = fopen("/proc/iomem", "r")) == NULL)
+ return;
+
+ kernel_code_range = symbol_value("__init_begin") - symbol_value("_text");
+
+ errflag = 1;
+ while (fgets(buf, BUFSIZE, iomem)) {
+ if (strstr(buf, ": System RAM")) {
+ clean_line(buf);
+
+ /*get end address of system ram region*/
+ if (!(p1 = strstr(buf, ":")))
+ continue;
+ *(p1-1) = NULLCHAR;
+ if (!(p1 = strstr(buf, "-")))
+ continue;
+ memory_end = htol(p1+1, RETURN_ON_ERROR | QUIET, NULL);
+ if (BADADDR == memory_end)
+ continue;
+
+ /*get start address of system ram region*/
+ *p1 = NULLCHAR;
+ memory_start = htol(buf, RETURN_ON_ERROR | QUIET, NULL);
+ if (BADADDR == memory_start)
+ continue;
+
+ /* system ram region is too small to load kernel code, find next region*/
+ if((memory_end - memory_start) < kernel_code_range)
+ continue;
+
+ errflag = 0;
+ break;
+ }
+ }
+ fclose(iomem);
+
+ if (errflag)
+ return;
+
+ offset = memory_start;
+ }else if (DISKDUMP_DUMPFILE())
+ return;
+ else if (KDUMP_DUMPFILE())
+ arm_kdump_phys_base(&offset); /*Get start address of first memory block*/
+ else{
+ error(WARNING,
+ "kimage_voffset cannot be determined from the dumpfile.\n");
+ error(CONT,
+ "Using default value of 0. If this is not correct, then try\n");
+ error(CONT,
+ "using the command line option: --machdep kimage_voffset=<addr>\n");
+ return;
+ }
+
+ ms->kimage_voffset = ms->vmalloc_start_addr + (kt->relocate * -1) - offset;
+}
static void
arm64_calc_phys_offset(void)
@@ -817,6 +898,7 @@ arm64_calc_phys_offset(void)
}
+
/*
* Determine PHYS_OFFSET either by reading VMCOREINFO or the kernel
* symbol, otherwise borrow the 32-bit ARM functionality.
--
1.9.1
--
Crash-utility mailing list
Crash-utility@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/crash-utility
