Ensure the fw_cfg overrides are parsed prior consuming any of said
overrides. fwcfg_get_u() treats zero as a valid overide value, which
is slightly problematic since the overrides are in the .bss and thus
initialized to zero.
Add a limit check when indexing fw_override so that future code doesn't
spontaneously explode.
Cc: Nadav Amit <nadav.amit@xxxxxxxxx>
Fixes: 03b1e4570f967 ("x86: Support environments without test-devices")
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
---
lib/x86/fwcfg.c | 10 ++++++++--
lib/x86/fwcfg.h | 2 --
x86/cstart64.S | 2 --
3 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/lib/x86/fwcfg.c b/lib/x86/fwcfg.c
index d8d797f..06ef62c 100644
--- a/lib/x86/fwcfg.c
+++ b/lib/x86/fwcfg.c
@@ -5,10 +5,11 @@
static struct spinlock lock;
static long fw_override[FW_CFG_MAX_ENTRY];
+static bool fw_override_done;
bool no_test_device;
-void read_cfg_override(void)
+static void read_cfg_override(void)
{
const char *str;
int i;
@@ -26,6 +27,8 @@ void read_cfg_override(void)
if ((str = getenv("TEST_DEVICE")))
no_test_device = !atol(str);
+
+ fw_override_done = true;
}
static uint64_t fwcfg_get_u(uint16_t index, int bytes)
@@ -34,7 +37,10 @@ static uint64_t fwcfg_get_u(uint16_t index, int bytes)
uint8_t b;
int i;
- if (fw_override[index] >= 0)
+ if (!fw_override_done)
+ read_cfg_override();
+
+ if (index < FW_CFG_MAX_ENTRY && fw_override[index] >= 0)
return fw_override[index];
spin_lock(&lock);
diff --git a/lib/x86/fwcfg.h b/lib/x86/fwcfg.h
index 88dc7a7..2f17461 100644
--- a/lib/x86/fwcfg.h
+++ b/lib/x86/fwcfg.h
@@ -36,8 +36,6 @@
extern bool no_test_device;
-void read_cfg_override(void);
-
static inline bool test_device_enabled(void)
{
return !no_test_device;
diff --git a/x86/cstart64.S b/x86/cstart64.S
index 23c1bd4..d4e4652 100644
--- a/x86/cstart64.S
+++ b/x86/cstart64.S
@@ -254,8 +254,6 @@ start64:
mov %rax, __args(%rip)
call __setup_args
- /* Read the configuration before running smp_init */
- call read_cfg_override
call smp_init
call enable_x2apic
--
2.22.0
