From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ifL7W-0005sv-3a for kexec@lists.infradead.org; Thu, 12 Dec 2019 09:50:56 +0000 Subject: Re: [PATCH] makedumpfile/s390: Add get_kaslr_offset() for s390x References: <20191203222725.64734-1-zaslonko@linux.ibm.com> <4AE2DC15AC0B8543882A74EA0D43DBEC03597AB9@BPXM09GP.gisp.nec.co.jp> From: Zaslonko Mikhail Message-ID: <323f61d4-6aab-a0b4-faa3-e41756fb9913@linux.ibm.com> Date: Thu, 12 Dec 2019 10:50:48 +0100 MIME-Version: 1.0 In-Reply-To: <4AE2DC15AC0B8543882A74EA0D43DBEC03597AB9@BPXM09GP.gisp.nec.co.jp> Content-Language: en-US List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Kazuhito Hagio , "kexec@lists.infradead.org" Cc: "prudo@linux.ibm.com" , "dyoung@redhat.com" Hello Kazu, I think we can try to generalize the kaslr offset extraction. I won't speak for other architectures, but for s390 that get_kaslr_offset_arm64() should work fine. The only concern of mine is this TODO statement: if (_text <= vaddr && vaddr <= _end) { DEBUG_MSG("info->kaslr_offset: %lx\n", info->kaslr_offset); return info->kaslr_offset; } else { /* * TODO: we need to check if it is vmalloc/vmmemmap/module * address, we will have different offset */ return 0; } Could you explain this one? Thanks, Mikhail On 09.12.2019 23:02, Kazuhito Hagio wrote: > Hi Mikhail, > > Sorry for late reply. > >> -----Original Message----- >> Since kernel v5.2 KASLR is supported on s390. In makedumpfile however no >> support has been added yet. This patch adds the arch specific function >> get_kaslr_offset() for s390x. >> Since the values in vmcoreinfo are already relocated, the patch is >> mainly relevant for vmlinux processing (-x option). > > In the current implementation of makedumpfile, the get_kaslr_offset(vaddr) > is supposed to return the KASLR offset only when the offset is needed to > add to the vaddr. So generally symbols from kernel (vmlinux) need it, but > symbols from modules are resolved dynamically and don't need the offset. \> > This patch always returns the offset if any, as a result, I guess this patch > will not work as expected with module symbols in filter config file. > > So... How about making get_kaslr_offset_arm64() general for other archs > (get_kaslr_offset_general() or something), then using it also for s390? > If OK, I can do that generalization. > > Thanks, > Kazu > >> >> Signed-off-by: Philipp Rudo >> Signed-off-by: Mikhail Zaslonko >> --- >> arch/s390x.c | 32 ++++++++++++++++++++++++++++++++ >> makedumpfile.h | 3 ++- >> 2 files changed, 34 insertions(+), 1 deletion(-) >> >> diff --git a/arch/s390x.c b/arch/s390x.c >> index bf9d58e..892df14 100644 >> --- a/arch/s390x.c >> +++ b/arch/s390x.c >> @@ -122,6 +122,38 @@ get_machdep_info_s390x(void) >> return TRUE; >> } >> >> +unsigned long >> +get_kaslr_offset_s390x(unsigned long vaddr) >> +{ >> + unsigned int i; >> + char buf[BUFSIZE_FGETS], *endp; >> + >> + if (!info->file_vmcoreinfo) >> + return FALSE; >> + >> + if (fseek(info->file_vmcoreinfo, 0, SEEK_SET) < 0) { >> + ERRMSG("Can't seek the vmcoreinfo file(%s). %s\n", >> + info->name_vmcoreinfo, strerror(errno)); >> + return FALSE; >> + } >> + >> + while (fgets(buf, BUFSIZE_FGETS, info->file_vmcoreinfo)) { >> + i = strlen(buf); >> + if (!i) >> + break; >> + if (buf[i - 1] == '\n') >> + buf[i - 1] = '\0'; >> + if (strncmp(buf, STR_KERNELOFFSET, >> + strlen(STR_KERNELOFFSET)) == 0) { >> + info->kaslr_offset = >> + strtoul(buf + strlen(STR_KERNELOFFSET), &endp, 16); >> + DEBUG_MSG("info->kaslr_offset: %lx\n", info->kaslr_offset); >> + } >> + } >> + >> + return info->kaslr_offset; >> +} >> + >> static int >> is_vmalloc_addr_s390x(unsigned long vaddr) >> { >> diff --git a/makedumpfile.h b/makedumpfile.h >> index ac11e90..26f6247 100644 >> --- a/makedumpfile.h >> +++ b/makedumpfile.h >> @@ -1071,11 +1071,12 @@ unsigned long long vaddr_to_paddr_ppc(unsigned long vaddr); >> int get_machdep_info_s390x(void); >> unsigned long long vaddr_to_paddr_s390x(unsigned long vaddr); >> int is_iomem_phys_addr_s390x(unsigned long addr); >> +unsigned long get_kaslr_offset_s390x(unsigned long vaddr); >> #define find_vmemmap() stub_false() >> #define get_phys_base() stub_true() >> #define get_machdep_info() get_machdep_info_s390x() >> #define get_versiondep_info() stub_true() >> -#define get_kaslr_offset(X) stub_false() >> +#define get_kaslr_offset(X) get_kaslr_offset_s390x(X) >> #define vaddr_to_paddr(X) vaddr_to_paddr_s390x(X) >> #define paddr_to_vaddr(X) paddr_to_vaddr_general(X) >> #define is_phys_addr(X) is_iomem_phys_addr_s390x(X) >> -- >> 2.17.1 >> > > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec