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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [RFC PATCH 3/4] xen/arm: initialize conditionally uninitialized local variables
This patch aims to fix some occurrences of possibly uninitialized
variables, that may be read before being written. This behaviour would
violate MISRA C:2012 Rule 9.1, besides being generally undesirable.
In all the analyzed cases, such accesses were actually safe, but it's
quite difficult to prove so by automatic checking, therefore a safer
route is to change the code so as to avoid the behaviour from occurring,
while preserving the semantics.
An initialization to a safe value is provided to reach this aim.
Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
---
Additional input on which values may be 'safe' in each context is
surely welcome, to avoid possibly compromising the correctness of
the function semantics.
---
xen/arch/arm/cpuerrata.c | 6 +++---
xen/arch/arm/domctl.c | 8 ++++----
xen/arch/arm/gic-v3-lpi.c | 17 +++++++++--------
xen/arch/arm/include/asm/p2m.h | 10 ++++++----
xen/arch/arm/platforms/xilinx-zynqmp-eemi.c | 10 ++--------
xen/arch/arm/psci.c | 10 +++++-----
xen/drivers/char/pl011.c | 2 +-
7 files changed, 30 insertions(+), 33 deletions(-)
diff --git a/xen/arch/arm/cpuerrata.c b/xen/arch/arm/cpuerrata.c
index d0658aedb6..14694c6081 100644
--- a/xen/arch/arm/cpuerrata.c
+++ b/xen/arch/arm/cpuerrata.c
@@ -159,7 +159,7 @@ extern char __mitigate_spectre_bhb_loop_start_32[],
static int enable_smccc_arch_workaround_1(void *data)
{
- struct arm_smccc_res res;
+ struct arm_smccc_res res = {0};
const struct arm_cpu_capabilities *entry = data;
/*
@@ -252,7 +252,7 @@ static int enable_spectre_bhb_workaround(void *data)
if ( cpus_have_cap(ARM_WORKAROUND_BHB_SMCC_3) )
{
- struct arm_smccc_res res;
+ struct arm_smccc_res res = {0};
if ( smccc_ver < SMCCC_VERSION(1, 1) )
goto warn;
@@ -393,7 +393,7 @@ DEFINE_PER_CPU_READ_MOSTLY(register_t,
ssbd_callback_required);
static bool has_ssbd_mitigation(const struct arm_cpu_capabilities *entry)
{
- struct arm_smccc_res res;
+ struct arm_smccc_res res = {0};
bool required;
if ( smccc_ver < SMCCC_VERSION(1, 1) )
diff --git a/xen/arch/arm/domctl.c b/xen/arch/arm/domctl.c
index ad56efb0f5..b38fed72be 100644
--- a/xen/arch/arm/domctl.c
+++ b/xen/arch/arm/domctl.c
@@ -29,10 +29,10 @@ static int handle_vuart_init(struct domain *d,
struct xen_domctl_vuart_op *vuart_op)
{
int rc;
- struct vpl011_init_info info;
-
- info.console_domid = vuart_op->console_domid;
- info.gfn = _gfn(vuart_op->gfn);
+ struct vpl011_init_info info = {
+ .console_domid = vuart_op->console_domid,
+ .gfn = _gfn(vuart_op->gfn)
+ };
if ( d->creation_finished )
return -EPERM;
diff --git a/xen/arch/arm/gic-v3-lpi.c b/xen/arch/arm/gic-v3-lpi.c
index eb0a5535e4..12f2af2e4d 100644
--- a/xen/arch/arm/gic-v3-lpi.c
+++ b/xen/arch/arm/gic-v3-lpi.c
@@ -210,7 +210,10 @@ out:
void gicv3_lpi_update_host_entry(uint32_t host_lpi, int domain_id,
uint32_t virt_lpi)
{
- union host_lpi *hlpip, hlpi;
+ union host_lpi *hlpip, hlpi = {
+ .virt_lpi = virt_lpi,
+ .dom_id = domain_id
+ };
ASSERT(host_lpi >= LPI_OFFSET);
@@ -218,9 +221,6 @@ void gicv3_lpi_update_host_entry(uint32_t host_lpi, int
domain_id,
hlpip = &lpi_data.host_lpis[host_lpi / HOST_LPIS_PER_PAGE][host_lpi %
HOST_LPIS_PER_PAGE];
- hlpi.virt_lpi = virt_lpi;
- hlpi.dom_id = domain_id;
-
write_u64_atomic(&hlpip->data, hlpi.data);
}
@@ -542,14 +542,15 @@ int gicv3_allocate_host_lpi_block(struct domain *d,
uint32_t *first_lpi)
for ( i = 0; i < LPI_BLOCK; i++ )
{
- union host_lpi hlpi;
-
/*
* Mark this host LPI as belonging to the domain, but don't assign
* any virtual LPI or a VCPU yet.
*/
- hlpi.virt_lpi = INVALID_LPI;
- hlpi.dom_id = d->domain_id;
+ union host_lpi hlpi = {
+ .virt_lpi = INVALID_LPI,
+ .dom_id = d->domain_id
+ };
+
write_u64_atomic(&lpi_data.host_lpis[chunk][lpi_idx + i].data,
hlpi.data);
diff --git a/xen/arch/arm/include/asm/p2m.h b/xen/arch/arm/include/asm/p2m.h
index 940495d42b..413e2a7add 100644
--- a/xen/arch/arm/include/asm/p2m.h
+++ b/xen/arch/arm/include/asm/p2m.h
@@ -345,7 +345,7 @@ static inline struct page_info *get_page_from_gfn(
struct domain *d, unsigned long gfn, p2m_type_t *t, p2m_query_t q)
{
mfn_t mfn;
- p2m_type_t _t;
+ p2m_type_t _t = p2m_invalid;
struct page_info *page;
/*
@@ -355,10 +355,12 @@ static inline struct page_info *get_page_from_gfn(
if ( likely(d != dom_xen) )
return p2m_get_page_from_gfn(d, _gfn(gfn), t);
- if ( !t )
+ /* Allow t to be NULL */
+ if ( t )
+ *t = _t;
+ else {
t = &_t;
-
- *t = p2m_invalid;
+ }
/*
* DOMID_XEN sees 1-1 RAM. The p2m_type is based on the type of the
diff --git a/xen/arch/arm/platforms/xilinx-zynqmp-eemi.c
b/xen/arch/arm/platforms/xilinx-zynqmp-eemi.c
index 2053ed7ac5..39d9ab4fa9 100644
--- a/xen/arch/arm/platforms/xilinx-zynqmp-eemi.c
+++ b/xen/arch/arm/platforms/xilinx-zynqmp-eemi.c
@@ -51,11 +51,11 @@ static inline bool domain_has_reset_access(struct domain
*d, uint32_t rst)
bool zynqmp_eemi(struct cpu_user_regs *regs)
{
- struct arm_smccc_res res;
+ struct arm_smccc_res res = {0};
uint32_t fid = get_user_reg(regs, 0);
uint32_t nodeid = get_user_reg(regs, 1);
unsigned int pm_fn = fid & 0xFFFF;
- enum pm_ret_status ret;
+ enum pm_ret_status ret = XST_PM_NO_ACCESS;
switch ( fid )
{
@@ -89,7 +89,6 @@ bool zynqmp_eemi(struct cpu_user_regs *regs)
{
gprintk(XENLOG_WARNING,
"zynqmp-pm: fn=%u No access to node %u\n", pm_fn, nodeid);
- ret = XST_PM_NO_ACCESS;
goto done;
}
goto forward_to_fw;
@@ -100,7 +99,6 @@ bool zynqmp_eemi(struct cpu_user_regs *regs)
{
gprintk(XENLOG_WARNING,
"zynqmp-pm: fn=%u No access to reset %u\n", pm_fn, nodeid);
- ret = XST_PM_NO_ACCESS;
goto done;
}
goto forward_to_fw;
@@ -116,7 +114,6 @@ bool zynqmp_eemi(struct cpu_user_regs *regs)
case EEMI_FID(PM_MMIO_READ):
gprintk(XENLOG_WARNING,
"zynqmp-pm: fn=%u No MMIO access to %u\n", pm_fn, nodeid);
- ret = XST_PM_NO_ACCESS;
goto done;
/* Exclusive to the hardware domain. */
@@ -146,14 +143,12 @@ bool zynqmp_eemi(struct cpu_user_regs *regs)
if ( !is_hardware_domain(current->domain) )
{
gprintk(XENLOG_WARNING, "eemi: fn=%u No access", pm_fn);
- ret = XST_PM_NO_ACCESS;
goto done;
}
goto forward_to_fw;
/* These calls are never allowed. */
case EEMI_FID(PM_SYSTEM_SHUTDOWN):
- ret = XST_PM_NO_ACCESS;
goto done;
case IPI_MAILBOX_FID(IPI_MAILBOX_OPEN):
@@ -166,7 +161,6 @@ bool zynqmp_eemi(struct cpu_user_regs *regs)
if ( !is_hardware_domain(current->domain) )
{
gprintk(XENLOG_WARNING, "IPI mailbox: fn=%u No access", pm_fn);
- ret = XST_PM_NO_ACCESS;
goto done;
}
goto forward_to_fw;
diff --git a/xen/arch/arm/psci.c b/xen/arch/arm/psci.c
index 695d2fa1f1..47e46af608 100644
--- a/xen/arch/arm/psci.c
+++ b/xen/arch/arm/psci.c
@@ -38,7 +38,7 @@ static uint32_t psci_cpu_on_nr;
int call_psci_cpu_on(int cpu)
{
- struct arm_smccc_res res;
+ struct arm_smccc_res res = {0};
arm_smccc_smc(psci_cpu_on_nr, cpu_logical_map(cpu), __pa(init_secondary),
&res);
@@ -50,7 +50,7 @@ void call_psci_cpu_off(void)
{
if ( psci_ver > PSCI_VERSION(0, 1) )
{
- struct arm_smccc_res res;
+ struct arm_smccc_res res = {0};
/* If successfull the PSCI cpu_off call doesn't return */
arm_smccc_smc(PSCI_0_2_FN32_CPU_OFF, &res);
@@ -73,7 +73,7 @@ void call_psci_system_reset(void)
static int __init psci_features(uint32_t psci_func_id)
{
- struct arm_smccc_res res;
+ struct arm_smccc_res res = {0};
if ( psci_ver < PSCI_VERSION(1, 0) )
return PSCI_NOT_SUPPORTED;
@@ -115,7 +115,7 @@ static void __init psci_init_smccc(void)
if ( psci_features(ARM_SMCCC_VERSION_FID) != PSCI_NOT_SUPPORTED )
{
- struct arm_smccc_res res;
+ struct arm_smccc_res res = {0};
arm_smccc_smc(ARM_SMCCC_VERSION_FID, &res);
if ( PSCI_RET(res) != ARM_SMCCC_NOT_SUPPORTED )
@@ -168,7 +168,7 @@ static int __init psci_init_0_2(void)
{ /* sentinel */ },
};
int ret;
- struct arm_smccc_res res;
+ struct arm_smccc_res res = {0};
if ( acpi_disabled )
{
diff --git a/xen/drivers/char/pl011.c b/xen/drivers/char/pl011.c
index f7bf3ad117..34ce90be52 100644
--- a/xen/drivers/char/pl011.c
+++ b/xen/drivers/char/pl011.c
@@ -285,7 +285,7 @@ static int __init pl011_dt_uart_init(struct dt_device_node
*dev,
const char *config = data;
int res;
paddr_t addr, size;
- uint32_t io_width;
+ uint32_t io_width = 0;
bool mmio32 = false, sbsa;
if ( strcmp(config, "") )
--
2.34.1
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