Author: hailfinger Date: Tue Feb 2 12:09:03 2010 New Revision: 889 URL: http://flashrom.org/trac/coreboot/changeset/889
Log: Create a physical memory mapping function which requests cached readonly memory. This should take care of picky Linux kernels which do not allow uncached mappings to cached areas. Handle mapping failure gracefully (no forced exit()) if the caller specifies it.
Such cached areas which can handle mapping failure are DMI tables and coreboot tables. On failure we just ignore those tables. That is not perfect, but a lot better than aborting flashrom due to an error in nonessential functionality.
This should fix flashrom on a sizable number of machines where it currently aborts early.
Yes, I could have exploited a Linux kernel bug to "solve" this, but relying on such bugs is not exactly the best idea.
Signed-off-by: Carl-Daniel Hailfinger c-d.hailfinger.devel.2006@gmx.net Acked-by: Vincent Pelletier plr.vincent@gmail.com
Modified: trunk/cbtable.c trunk/flash.h trunk/physmap.c
Modified: trunk/cbtable.c ============================================================================== --- trunk/cbtable.c Mon Feb 1 06:49:46 2010 (r888) +++ trunk/cbtable.c Tue Feb 2 12:09:03 2010 (r889) @@ -6,6 +6,7 @@ * (Written by Eric Biederman ebiederman@lnxi.com for Linux Networx) * Copyright (C) 2006-2009 coresystems GmbH * (Written by Stefan Reinauer stepan@coresystems.de for coresystems GmbH) + * Copyright (C) 2010 Carl-Daniel Hailfinger * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -207,11 +208,15 @@ #else start = 0x0; #endif - table_area = physmap("low megabyte", start, BYTES_TO_MAP); + table_area = physmap_try_ro("low megabyte", start, BYTES_TO_MAP - start); + if (!table_area) { + msg_perr("Failed getting access to coreboot low tables.\n"); + return -1; + }
lb_table = find_lb_table(table_area, 0x00000, 0x1000); if (!lb_table) - lb_table = find_lb_table(table_area, 0xf0000, BYTES_TO_MAP); + lb_table = find_lb_table(table_area, 0xf0000 - start, BYTES_TO_MAP - start); if (lb_table) { struct lb_forward *forward = (struct lb_forward *) (((char *)lb_table) + lb_table->header_bytes); @@ -219,7 +224,12 @@ start = forward->forward; start &= ~(getpagesize() - 1); physunmap(table_area, BYTES_TO_MAP); - table_area = physmap("high tables", start, BYTES_TO_MAP); + table_area = physmap_try_ro("high tables", start, BYTES_TO_MAP); + if (!table_area) { + msg_perr("Failed getting access to coreboot " + "high tables.\n"); + return -1; + } lb_table = find_lb_table(table_area, 0x00000, 0x1000); } }
Modified: trunk/flash.h ============================================================================== --- trunk/flash.h Mon Feb 1 06:49:46 2010 (r888) +++ trunk/flash.h Tue Feb 2 12:09:03 2010 (r889) @@ -343,6 +343,7 @@
/* physmap.c */ void *physmap(const char *descr, unsigned long phys_addr, size_t len); +void *physmap_try_ro(const char *descr, unsigned long phys_addr, size_t len); void physunmap(void *virt_addr, size_t len); int setup_cpu_msr(int cpu); void cleanup_cpu_msr(void);
Modified: trunk/physmap.c ============================================================================== --- trunk/physmap.c Mon Feb 1 06:49:46 2010 (r888) +++ trunk/physmap.c Tue Feb 2 12:09:03 2010 (r889) @@ -3,6 +3,7 @@ * * Copyright (C) 2009 Peter Stuge peter@stuge.se * Copyright (C) 2009 coresystems GmbH + * Copyright (C) 2010 Carl-Daniel Hailfinger * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -36,6 +37,10 @@ return map_physical(phys_addr, len); }
+/* The OS X driver does not differentiate between mapping types. */ +#define sys_physmap_rw_uncached sys_physmap +#define sys_physmap_ro_cached sys_physmap + void physunmap(void *virt_addr, size_t len) { unmap_physical(virt_addr, len); @@ -51,8 +56,10 @@ #endif
static int fd_mem = -1; +static int fd_mem_cached = -1;
-void *sys_physmap(unsigned long phys_addr, size_t len) +/* For MMIO access. Must be uncached, doesn't make sense to restrict to ro. */ +void *sys_physmap_rw_uncached(unsigned long phys_addr, size_t len) { void *virt_addr;
@@ -69,6 +76,26 @@ return MAP_FAILED == virt_addr ? NULL : virt_addr; }
+/* For reading DMI/coreboot/whatever tables. We should never write, and we + * do not care about caching. + */ +void *sys_physmap_ro_cached(unsigned long phys_addr, size_t len) +{ + void *virt_addr; + + if (-1 == fd_mem_cached) { + /* Open the memory device CACHED. */ + if (-1 == (fd_mem_cached = open(MEM_DEV, O_RDWR))) { + perror("Critical error: open(" MEM_DEV ")"); + exit(2); + } + } + + virt_addr = mmap(0, len, PROT_READ, MAP_SHARED, + fd_mem_cached, (off_t)phys_addr); + return MAP_FAILED == virt_addr ? NULL : virt_addr; +} + void physunmap(void *virt_addr, size_t len) { if (len == 0) { @@ -80,7 +107,12 @@ } #endif
-void *physmap(const char *descr, unsigned long phys_addr, size_t len) +#define PHYSMAP_NOFAIL 0 +#define PHYSMAP_MAYFAIL 1 +#define PHYSMAP_RW 0 +#define PHYSMAP_RO 1 + +void *physmap_common(const char *descr, unsigned long phys_addr, size_t len, int mayfail, int readonly) { void *virt_addr;
@@ -100,7 +132,11 @@ descr, (unsigned long)len, phys_addr); }
- virt_addr = sys_physmap(phys_addr, len); + if (readonly) { + virt_addr = sys_physmap_ro_cached(phys_addr, len); + } else { + virt_addr = sys_physmap_rw_uncached(phys_addr, len); + }
if (NULL == virt_addr) { if (NULL == descr) @@ -114,12 +150,23 @@ fprintf(stderr, "You can override CONFIG_X86_PAT at boot with the nopat kernel parameter but\n"); fprintf(stderr, "disabling the other option unfortunately requires a kernel recompile. Sorry!\n"); } - exit(3); + if (!mayfail) + exit(3); }
return virt_addr; }
+void *physmap(const char *descr, unsigned long phys_addr, size_t len) +{ + return physmap_common(descr, phys_addr, len, PHYSMAP_NOFAIL, PHYSMAP_RW); +} + +void *physmap_try_ro(const char *descr, unsigned long phys_addr, size_t len) +{ + return physmap_common(descr, phys_addr, len, PHYSMAP_MAYFAIL, PHYSMAP_RO); +} + #ifdef __linux__ /* * Reading and writing to MSRs, however requires instructions rdmsr/wrmsr,