Previously the default implementation was used, which always failed.
On other systems than the Geode the code is not equal to that anymore,
but should not explode because setup_cpu_msr() returns an error and
therefore no other MSR functions should be called.
Signed-off-by: Stefan Tauner <stefan.tauner(a)student.tuwien.ac.at>
---
physmap.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 84 insertions(+), 10 deletions(-)
diff --git a/physmap.c b/physmap.c
index 4ebfb06..b6a9163 100644
--- a/physmap.c
+++ b/physmap.c
@@ -282,6 +282,8 @@ void *physmap_try_ro(const char *descr, unsigned long phys_addr, size_t len)
PHYSMAP_RO);
}
+/* MSR abstraction implementations for Linux, OpenBSD, FreeBSD/Dragonfly, OSX, libpayload
+ * and a non-working default implemenation on the bottom. See also hwaccess.h for some (re)declarations. */
#if defined(__i386__) || defined(__x86_64__)
#ifdef __linux__
@@ -381,8 +383,83 @@ void cleanup_cpu_msr(void)
/* Clear MSR file descriptor. */
fd_msr = -1;
}
-#else
-#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
+#elif defined(__OpenBSD__) /* This does only work for certain AMD Geode LX systems see amdmsr(4). */
+#include <sys/ioctl.h>
+#include <machine/amdmsr.h>
+
+static int fd_msr = -1;
+
+msr_t rdmsr(int addr)
+{
+ struct amdmsr_req args;
+
+ msr_t msr = { 0xffffffff, 0xffffffff };
+
+ args.addr = (uint32_t)addr;
+
+ if (ioctl(fd_msr, RDMSR, &args) < 0) {
+ msg_perr("Error while executing RDMSR ioctl: %s\n", strerror(errno));
+ close(fd_msr);
+ exit(1);
+ }
+
+ msr.lo = args.val & 0xffffffff;
+ msr.hi = args.val >> 32;
+
+ return msr;
+}
+
+int wrmsr(int addr, msr_t msr)
+{
+ struct amdmsr_req args;
+
+ args.msr = addr;
+ args.val = (((uint64_t)msr.hi) << 32) | msr.lo;
+
+ if (ioctl(fd_msr, WRMSR, &args) < 0) {
+ msg_perr("Error while executing WRMSR ioctl: %s\n", strerror(errno));
+ close(fd_msr);
+ exit(1);
+ }
+
+ return 0;
+}
+
+int setup_cpu_msr(int cpu)
+{
+ char msrfilename[64];
+ memset(msrfilename, 0, sizeof(msrfilename));
+ snprintf(msrfilename, sizeof(msrfilename), "/dev/amdmsr");
+
+ if (fd_msr != -1) {
+ msg_pinfo("MSR was already initialized\n");
+ return -1;
+ }
+
+ fd_msr = open(msrfilename, O_RDWR);
+
+ if (fd_msr < 0) {
+ msg_perr("Error while opening %s: %s\n", msrfilename, strerror(errno));
+ return -1;
+ }
+
+ return 0;
+}
+
+void cleanup_cpu_msr(void)
+{
+ if (fd_msr == -1) {
+ msg_pinfo("No MSR initialized.\n");
+ return;
+ }
+
+ close(fd_msr);
+
+ /* Clear MSR file descriptor. */
+ fd_msr = -1;
+}
+
+#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
#include <sys/ioctl.h>
typedef struct {
@@ -465,9 +542,7 @@ void cleanup_cpu_msr(void)
fd_msr = -1;
}
-#else
-
-#if defined(__MACH__) && defined(__APPLE__)
+#elif defined(__MACH__) && defined(__APPLE__)
int setup_cpu_msr(int cpu)
{
// Always succeed for now
@@ -494,6 +569,7 @@ int libpayload_wrmsr(int addr, msr_t msr)
return 0;
}
#else
+/* default MSR implementation */
msr_t rdmsr(int addr)
{
msr_t ret = { 0xffffffff, 0xffffffff };
@@ -516,9 +592,7 @@ void cleanup_cpu_msr(void)
{
// Nothing, yet.
}
-#endif
-#endif
-#endif
-#else
+#endif // OS switches for MSR code
+#else // x86
/* Does MSR exist on non-x86 architectures? */
-#endif
+#endif // arch switches for MSR code
--
Kind regards, Stefan Tauner