Add SYSCTL to get KERNBASE and relocated KERNBASE
This change adds 2 new SYSCTLs, to retrieve the original and relocated KERNBASE values. This provides an easy, architecture independent way to calculate the running kernel displacement (current/load address minus original base address). The initial goal for this change is to add a new libkvm function that returns the kernel displacement, both for live kernels and crashdumps. This would in turn be used by kgdb to find out how to relocate kernel symbols (if needed). Reviewed by: jhb Differential Revision: https://reviews.freebsd.org/D23284
This commit is contained in:
parent
7503958e4c
commit
eb5a41cf2f
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=357570
@ -51,6 +51,7 @@ __FBSDID("$FreeBSD$");
|
||||
#include <sys/fcntl.h>
|
||||
#include <sys/vnode.h>
|
||||
#include <sys/linker.h>
|
||||
#include <sys/sysctl.h>
|
||||
|
||||
#include <machine/elf.h>
|
||||
|
||||
@ -389,6 +390,13 @@ link_elf_link_common_finish(linker_file_t lf)
|
||||
|
||||
extern vm_offset_t __startkernel, __endkernel;
|
||||
|
||||
static unsigned long kern_relbase = KERNBASE;
|
||||
|
||||
SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
|
||||
SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
|
||||
SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
|
||||
&kern_relbase, 0, "Kernel relocated base address");
|
||||
|
||||
static void
|
||||
link_elf_init(void* arg)
|
||||
{
|
||||
@ -431,6 +439,7 @@ link_elf_init(void* arg)
|
||||
#ifdef __powerpc__
|
||||
linker_kernel_file->address = (caddr_t)__startkernel;
|
||||
linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
|
||||
kern_relbase = (unsigned long)__startkernel;
|
||||
#else
|
||||
linker_kernel_file->address += KERNBASE;
|
||||
linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;
|
||||
|
Loading…
Reference in New Issue
Block a user