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authorJan Luebbe <jlu@pengutronix.de>2014-08-03 17:51:38 +0200
committerSascha Hauer <s.hauer@pengutronix.de>2015-02-27 13:17:31 +0100
commitd8a6e1c2662aad2f5d9b4050a276b8e6b9fbb3b1 (patch)
treea332558261dc513a9b585e0e3e91ba6c9ad29445 /common/memory_display.c
parentb42a3e2f68f97464d60110c58ba5f5f0e4bc333b (diff)
downloadbarebox-d8a6e1c2662aad2f5d9b4050a276b8e6b9fbb3b1.tar.gz
ARM/mem: handle data aborts gracefully for md
Sometimes memory ranges contain inaccessible registers which trigger a data abort when accessed. To handle this gracefully, we extend the data abort exception handler to ignore the exception when configured to do so. This allows detecting inaccessible memory from the md command. It will show XX for unreadable bytes instead. The previous behaviour: barebox@TI AM335x BeagleBone:/ md 0x50000000 unable to handle paging request at address 0x500000ac pc : [<8fe2e0dc>] lr : [<8fe2e0b9>] sp : 8ffff898 ip : 00000024 fp : 00000000 r10: 8bfa0204 r9 : 00000000 r8 : 8bfa0204 r7 : 00000100 r6 : 50000000 r5 : 8bfa0204 r4 : 00000004 r3 : 00000f00 r2 : 000000ac r1 : 00000004 r0 : 00000014 Flags: nZCv IRQs off FIQs on Mode SVC_32 [<8fe2e0dc>] (memcpy_sz+0x40/0x48) from [<8fe2f337>] (mem_read+0x3b/0x48) [<8fe2f337>] (mem_read+0x3b/0x48) from [<8fe2bb13>] (cdev_read+0x25/0x2e) [<8fe2bb13>] (cdev_read+0x25/0x2e) from [<8fe2c15b>] (devfs_read+0x1b/0x1e) [<8fe2c15b>] (devfs_read+0x1b/0x1e) from [<8fe2df5b>] (__read+0x43/0x5c) [<8fe2df5b>] (__read+0x43/0x5c) from [<8fe2e61f>] (read+0x2b/0x48) [<8fe2e61f>] (read+0x2b/0x48) from [<8fe1e4a5>] (do_mem_md+0xc1/0x144) [<8fe1e4a5>] (do_mem_md+0xc1/0x144) from [<8fe02889>] (execute_command+0x21/0x48) [<8fe02889>] (execute_command+0x21/0x48) from [<8fe061c1>] (run_list_real+0x549/0x634) [<8fe061c1>] (run_list_real+0x549/0x634) from [<8fe05b43>] (parse_stream_outer+0xdb/0x174) [<8fe05b43>] (parse_stream_outer+0xdb/0x174) from [<8fe06435>] (run_shell+0x29/0x54) [<8fe06435>] (run_shell+0x29/0x54) from [<8fe02889>] (execute_command+0x21/0x48) [<8fe02889>] (execute_command+0x21/0x48) from [<8fe061c1>] (run_list_real+0x549/0x634) [<8fe061c1>] (run_list_real+0x549/0x634) from [<8fe05efb>] (run_list_real+0x283/0x634) [<8fe31e1d>] (unwind_backtrace+0x1/0x64) from [<8fe24e61>] (panic+0x1d/0x34) [<8fe24e61>] (panic+0x1d/0x34) from [<8fe322c1>] (do_exception+0xd/0x10) [<8fe322c1>] (do_exception+0xd/0x10) from [<8fe32329>] (do_data_abort+0x21/0x2c) [<8fe32329>] (do_data_abort+0x21/0x2c) from [<8fe31fe8>] (data_abort+0x48/0x60) The new behaviour: barebox@TI AM335x BeagleBone:/ md 0x50000000 50000000: 00000060 00000000 00000000 00000000 `............... 50000010: 00000000 00000001 00000000 00000000 ................ 50000020: 00000000 00000000 00000000 00000000 ................ 50000030: 00000000 00000000 00000000 00000000 ................ 50000040: 00001ff0 400000ac 00000211 00000000 .......@........ 50000050: 00000a00 00000001 00000000 00000000 ................ 50000060: 00000000 00101001 22060514 10057016 ...........".p.. 50000070: 010f1111 8f070000 00000f40 00000000 ........@....... 50000080: 00000000 00000000 00000000 00000000 ................ 50000090: 00001000 00101001 22060514 10057016 ...........".p.. 500000a0: 010f1111 8f070000 00000f00 XXXXXXXX ................ 500000b0: XXXXXXXX XXXXXXXX 00000000 00000000 ................ 500000c0: 00001000 00101001 22060514 10057016 ...........".p.. 500000d0: 010f1111 8f070000 00000f00 XXXXXXXX ................ 500000e0: XXXXXXXX XXXXXXXX 00000000 00000000 ................ 500000f0: 00001000 00101001 22060514 10057016 ...........".p.. The current implementation breaks everything except ARM and takes several shortcuts which need to be implemented more cleanly. Suggestions are very welcome! Signed-off-by: Jan Luebbe <jlu@pengutronix.de> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'common/memory_display.c')
-rw-r--r--common/memory_display.c34
1 files changed, 29 insertions, 5 deletions
diff --git a/common/memory_display.c b/common/memory_display.c
index c8ae57a..7b1d35e 100644
--- a/common/memory_display.c
+++ b/common/memory_display.c
@@ -1,5 +1,6 @@
#include <common.h>
#include <errno.h>
+#include <abort.h>
#define DISP_LINE_LEN 16
@@ -26,18 +27,41 @@ int memory_display(const void *addr, loff_t offs, unsigned nbytes, int size, int
for (i = 0; i < linebytes; i += size) {
if (size == 4) {
u32 res;
- res = (*uip++ = *((uint *)addr));
+ data_abort_mask();
+ res = *((uint *)addr);
if (swab)
res = __swab32(res);
- count -= printf(" %08x", res);
+ if (data_abort_unmask()) {
+ res = 0xffffffff;
+ count -= printf(" xxxxxxxx");
+ } else {
+ count -= printf(" %08x", res);
+ }
+ *uip++ = res;
} else if (size == 2) {
u16 res;
- res = (*usp++ = *((ushort *)addr));
+ data_abort_mask();
+ res = *((ushort *)addr);
if (swab)
res = __swab16(res);
- count -= printf(" %04x", res);
+ if (data_abort_unmask()) {
+ res = 0xffff;
+ count -= printf(" xxxx");
+ } else {
+ count -= printf(" %04x", res);
+ }
+ *usp++ = res;
} else {
- count -= printf(" %02x", (*ucp++ = *((u_char *)addr)));
+ u8 res;
+ data_abort_mask();
+ res = *((u_char *)addr);
+ if (data_abort_unmask()) {
+ res = 0xff;
+ count -= printf(" xx");
+ } else {
+ count -= printf(" %02x", res);
+ }
+ *ucp++ = res;
}
addr += size;
offs += size;