On Fri, Feb 25, 2022 at 1:01 AM <[email protected]> wrote:
> Date: Thu, 24 Feb 2022 11:52:12 +0800 > From: Pingfan Liu <[email protected]> > To: [email protected] > Subject: [Crash-utility] [PATCHv2] arm64: deduce the start address of > kernel code, based on kernel version > Message-ID: <[email protected]> > > After kernel commit e2a073dde921 ("arm64: omit [_text, _stext) from > permanent kernel mapping"), the range [_text, _stext] is reclaimed. But > the current crash code still assumes kernel starting from "_text". > > Thank you for the fix, Pingfan. Good findings. The v2 looks good and the test is ok. Applied. Lianbo This change only affects the vmalloced area on arm64 and may result a > false in arm64_IS_VMALLOC_ADDR(). > > Since vmcore has no extra information about this trival change, it can > only be deduced from kernel version, which means ms->kimage_text can not > be correctly initialized until kernel_init() finishes. Here on arm64, it > can be done at the point machdep_init(POST_GDB). This is fine > since there is no access to vmalloced area at this stage. > > Signed-off-by: Pingfan Liu <[email protected]> > --- > arm64.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/arm64.c b/arm64.c > index de1038a..3ab8489 100644 > --- a/arm64.c > +++ b/arm64.c > @@ -92,6 +92,20 @@ static void arm64_calc_VA_BITS(void); > static int arm64_is_uvaddr(ulong, struct task_context *); > static void arm64_calc_KERNELPACMASK(void); > > +static void arm64_calc_kernel_start(void) > +{ > + struct machine_specific *ms = machdep->machspec; > + struct syment *sp; > + > + if (THIS_KERNEL_VERSION >= LINUX(5,11,0)) > + sp = kernel_symbol_search("_stext"); > + else > + sp = kernel_symbol_search("_text"); > + > + ms->kimage_text = (sp ? sp->value : 0); > + sp = kernel_symbol_search("_end"); > + ms->kimage_end = (sp ? sp->value : 0); > +} > > /* > * Do all necessary machine-specific setup here. This is called several > times > @@ -241,6 +255,7 @@ arm64_init(int when) > if (machdep->flags & NEW_VMEMMAP) { > struct syment *sp; > > + /* It is finally decided in > arm64_calc_kernel_start() */ > sp = kernel_symbol_search("_text"); > ms->kimage_text = (sp ? sp->value : 0); > sp = kernel_symbol_search("_end"); > @@ -387,6 +402,8 @@ arm64_init(int when) > break; > > case POST_GDB: > + /* Rely on kernel version to decide the kernel start > address */ > + arm64_calc_kernel_start(); > arm64_calc_virtual_memory_ranges(); > arm64_get_section_size_bits(); > > -- > 2.31.1 >
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