Jonathan Neuschäfer (j.neuschaefer@gmx.net) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/16015
-gerrit
commit 877ded79fe0e3cc1e76d0396f77ae2c67af66bd3 Author: Jonathan Neuschäfer j.neuschaefer@gmx.net Date: Mon Aug 22 19:37:15 2016 +0200
arch/riscv: Print the page table structure after construction
A new Kconfig option, DEBUG_PRINT_PAGE_TABLES, is added to control this behaviour. It is currently only available on RISC-V, but other architectures can use it, too, should the need arise.
Change-Id: I52a863d8bc814ab3ed3a1f141d0a77edc6e4044d Signed-off-by: Jonathan Neuschäfer j.neuschaefer@gmx.net --- src/Kconfig | 8 ++++ src/arch/riscv/include/vm.h | 2 +- src/arch/riscv/virtual_memory.c | 85 +++++++++++++++++++++++++++++++++++++---- 3 files changed, 86 insertions(+), 9 deletions(-)
diff --git a/src/Kconfig b/src/Kconfig index 7db491f..64da061 100644 --- a/src/Kconfig +++ b/src/Kconfig @@ -1127,6 +1127,14 @@ config DEBUG_BOOT_STATE Control debugging of the boot state machine. When selected displays the state boundaries in ramstage.
+config DEBUG_PRINT_PAGE_TABLES + bool "Print the page tables after construction" + default n + depends on ARCH_RISCV + help + After the page tables have been built, print them on the debug + console. + endmenu
# These probably belong somewhere else, but they are needed somewhere. diff --git a/src/arch/riscv/include/vm.h b/src/arch/riscv/include/vm.h index 5bf03c7..cc26b13 100644 --- a/src/arch/riscv/include/vm.h +++ b/src/arch/riscv/include/vm.h @@ -63,7 +63,7 @@ size_t pte_ppn(pte_t pte); pte_t ptd_create(uintptr_t ppn); pte_t pte_create(uintptr_t ppn, int prot, int user);
-void walk_page_table(void); +void print_page_table(void);
void init_vm(uintptr_t virtMemStart, uintptr_t physMemStart, uintptr_t pageTableStart); void mstatus_init(void); // need to setup mstatus so we know we have virtual memory diff --git a/src/arch/riscv/virtual_memory.c b/src/arch/riscv/virtual_memory.c index bbbba7a..bea552d 100644 --- a/src/arch/riscv/virtual_memory.c +++ b/src/arch/riscv/virtual_memory.c @@ -23,11 +23,77 @@
pte_t* root_page_table;
-void walk_page_table(void) { - // TODO: implement a full walk to make sure memory was set up - //const size_t pte_per_page = RISCV_PGSIZE/sizeof(void*); - pte_t* t = root_page_table; - printk(BIOS_DEBUG, "root_page_table: %p\n", t); +/* Indent the following text by 2*level spaces */ +static void indent(int level) +{ + int i; + for (i = 0; i < level; i++) + printk(BIOS_DEBUG, " "); +} + +/* + * Convert a page table index at a given page table level to a virtual address + * offset + */ +static uintptr_t index_to_virt_addr(int index, int level) +{ + /* + * Index is at most RISCV_PGLEVEL_BITS bits wide (not considering the + * leading zeroes. If level==0, the below expression thus shifts index + * into the highest bits of a 64-bit number, and then shifts it down + * with sign extension. + * + * If level>0, then the expression should work as expected, without any + * magic. + */ + return ((intptr_t)index) + << (64 - RISCV_PGLEVEL_BITS - level * RISCV_PGLEVEL_BITS) + >> (64 - VA_BITS); +} + +/* Dump the page table structures to the console -- helper function */ +static void print_page_table_at(pte_t *pt, intptr_t virt_addr, int level) +{ + int i; + + indent(level); + printk(BIOS_DEBUG, "Level %d page table at 0x%p\n", level, pt); + + for (i = 0; i < RISCV_PGSIZE / sizeof(pte_t); i++) { + char urwx[8]; + uintptr_t pointer; + intptr_t next_virt_addr; + + if (!(pt[i] & PTE_V)) + continue; + + urwx[0] = (pt[i] & PTE_U)? 'u' : '-'; + urwx[1] = (pt[i] & PTE_R)? 'r' : '-'; + urwx[2] = (pt[i] & PTE_W)? 'w' : '-'; + urwx[3] = (pt[i] & PTE_X)? 'x' : '-'; + urwx[4] = '\0'; + + next_virt_addr = virt_addr + index_to_virt_addr(i, level); + + pointer = ((uintptr_t)pt[i] >> 10) << RISCV_PGSHIFT; + + indent(level + 1); + printk(BIOS_DEBUG, "Valid PTE at index %d (0x%016zx -> 0x%zx), ", + i, (size_t) next_virt_addr, (size_t) pointer); + if (PTE_TABLE(pt[i])) + printk(BIOS_DEBUG, "page table\n"); + else + printk(BIOS_DEBUG, "protections %s\n", urwx); + + if (PTE_TABLE(pt[i])) { + print_page_table_at((pte_t *)pointer, next_virt_addr, level + 1); + } + } +} + +/* Print the page table structures to the console */ +void print_page_table(void) { + print_page_table_at(root_page_table, 0, 0); }
void flush_tlb(void) @@ -124,14 +190,17 @@ void initVirtualMemory(void) { uintptr_t pageTableStart = 0x1400000; init_vm(virtualStart, physicalStart, pageTableStart); mb(); + +#if IS_ENABLED(CONFIG_DEBUG_PRINT_PAGE_TABLES) printk(BIOS_DEBUG, "Finished initializing virtual memory, starting walk...\n"); - walk_page_table(); + print_page_table(); +#else + printk(BIOS_DEBUG, "Finished initializing virtual memory\n"); +#endif }
void mstatus_init(void) { - // supervisor support is required - uintptr_t ms = 0; ms = INSERT_FIELD(ms, MSTATUS_FS, 3); ms = INSERT_FIELD(ms, MSTATUS_XS, 3);