From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x241.google.com (mail-pf0-x241.google.com [IPv6:2607:f8b0:400e:c00::241]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3yFkRt3vtTzDrJT for ; Mon, 16 Oct 2017 14:33:14 +1100 (AEDT) Received: by mail-pf0-x241.google.com with SMTP id b6so6387897pfh.7 for ; Sun, 15 Oct 2017 20:33:14 -0700 (PDT) From: Balbir Singh To: mpe@ellerman.id.au Cc: linuxppc-dev@lists.ozlabs.org, Balbir Singh Subject: [PATCH v2] powerpc/xmon: Support dumping software pagetables Date: Mon, 16 Oct 2017 14:33:02 +1100 Message-Id: <20171016033302.7814-1-bsingharora@gmail.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , It would be nice to be able to dump page tables in a particular context. eg: dumping vmalloc space: 0:mon> dv 0xd00037fffff00000 pgd @ 0xc0000000017c0000 pgdp @ 0xc0000000017c00d8 = 0x00000000f10b1000 pudp @ 0xc0000000f10b13f8 = 0x00000000f10d0000 pmdp @ 0xc0000000f10d1ff8 = 0x00000000f1102000 ptep @ 0xc0000000f1102780 = 0xc0000000f1ba018e Maps physical address = 0x00000000f1ba0000 Flags = Accessed Dirty Read Write This patch does not replicate the complex code of dump_pagetable and has no support for bolted linear mapping, thats why I've it's called dump virtual page table support. The format of the PTE can be expanded even further to add more useful information about the flags in the PTE if required. Signed-off-by: Balbir Singh [mpe: Bike shed the output format, show the pgdir] Signed-off-by: Michael Ellerman --- Changelog v2 - fix powerpc 32 build error, include highmem.h - remove double semicolon's in format_pte arch/powerpc/xmon/xmon.c | 112 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 112 insertions(+) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index 33351c6..5e30fc3 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -127,6 +128,7 @@ static void byterev(unsigned char *, int); static void memex(void); static int bsesc(void); static void dump(void); +static void show_pte(unsigned long); static void prdump(unsigned long, long); static int ppc_inst_dump(unsigned long, long, int); static void dump_log_buf(void); @@ -234,6 +236,7 @@ Commands:\n\ #endif "\ dr dump stream of raw bytes\n\ + dv dump virtual address translation \n\ dt dump the tracing buffers (uses printk)\n\ dtc dump the tracing buffers for current CPU (uses printk)\n\ " @@ -2574,6 +2577,9 @@ dump(void) dump_log_buf(); } else if (c == 'o') { dump_opal_msglog(); + } else if (c == 'v') { + /* dump virtual to physical translation */ + show_pte(adrs); } else if (c == 'r') { scanhex(&ndump); if (ndump == 0) @@ -2907,6 +2913,112 @@ static void show_task(struct task_struct *tsk) tsk->comm); } +void format_pte(void *ptep, unsigned long pte) +{ + printf("ptep @ 0x%016lx = 0x%016lx\n", (unsigned long)ptep, pte); + printf("Maps physical address = 0x%016lx\n", pte & PTE_RPN_MASK); + + printf("Flags = %s%s%s%s%s\n", + (pte & _PAGE_ACCESSED) ? "Accessed " : "", + (pte & _PAGE_DIRTY) ? "Dirty " : "", + (pte & _PAGE_READ) ? "Read " : "", + (pte & _PAGE_WRITE) ? "Write " : "", + (pte & _PAGE_EXEC) ? "Exec " : ""); +} + +static void show_pte(unsigned long addr) +{ + unsigned long tskv = 0; + struct task_struct *tsk = NULL; + struct mm_struct *mm; + pgd_t *pgdp, *pgdir; + pud_t *pudp; + pmd_t *pmdp; + pte_t *ptep; + + if (!scanhex(&tskv)) + mm = &init_mm; + else + tsk = (struct task_struct *)tskv; + + if (tsk == NULL) + mm = &init_mm; + else + mm = tsk->active_mm; + + if (setjmp(bus_error_jmp) != 0) { + catch_memory_errors = 0; + printf("*** Error dumping pte for task %p\n", tsk); + return; + } + + catch_memory_errors = 1; + sync(); + + if (mm == &init_mm) { + pgdp = pgd_offset_k(addr); + pgdir = pgd_offset_k(0); + } else { + pgdp = pgd_offset(mm, addr); + pgdir = pgd_offset(mm, 0); + } + + if (pgd_none(*pgdp)) { + printf("no linux page table for address\n"); + return; + } + + printf("pgd @ 0x%016lx\n", pgdir); + + if (pgd_huge(*pgdp)) { + format_pte(pgdp, pgd_val(*pgdp)); + return; + } + printf("pgdp @ 0x%016lx = 0x%016lx\n", pgdp, pgd_val(*pgdp)); + + pudp = pud_offset(pgdp, addr); + + if (pud_none(*pudp)) { + printf("No valid PUD\n"); + return; + } + +#ifdef CONFIG_HUGETLB_PAGE + if (pud_huge(*pudp)) { + format_pte(pudp, pud_val(*pudp)); + return; + } +#endif + + printf("pudp @ 0x%016lx = 0x%016lx\n", pudp, pud_val(*pudp)); + + pmdp = pmd_offset(pudp, addr); + + if (pmd_none(*pmdp)) { + printf("No valid PMD\n"); + return; + } + +#ifdef CONFIG_HUGETLB_PAGE + if (pmd_huge(*pmdp)) { + format_pte(pmdp, pmd_val(*pmdp)); + return; + } +#endif + printf("pmdp @ 0x%016lx = 0x%016lx\n", pmdp, pmd_val(*pmdp)); + + ptep = pte_offset_map(pmdp, addr); + if (pte_none(*ptep)) { + printf("no valid PTE\n"); + return; + } + + format_pte(ptep, pte_val(*ptep)); + + sync(); + __delay(200); + catch_memory_errors = 0; +} static void show_tasks(void) { unsigned long tskv; -- 2.9.5