From 90f6e9b0856fc1c9fdf1195c0c5c43d3b58426c1 Mon Sep 17 00:00:00 2001
From: "Suren A. Chilingaryan" <csa@suren.me>
Date: Wed, 5 Aug 2015 15:26:53 +0200
Subject: Protect with locks the initialization of software registers
---
protocols/software.c | 39 ++++++++++++++++++++++++++++++++++-----
1 file changed, 34 insertions(+), 5 deletions(-)
diff --git a/protocols/software.c b/protocols/software.c
index e1339a6..ed9d372 100644
--- a/protocols/software.c
+++ b/protocols/software.c
@@ -13,10 +13,10 @@
typedef struct pcilib_software_register_bank_context_s pcilib_software_register_bank_context_t;
struct pcilib_software_register_bank_context_s {
- pcilib_register_bank_context_t bank_ctx;
+ pcilib_register_bank_context_t bank_ctx; /**< the bank context associated with the software registers */
- pcilib_kmem_handle_t *kmem;
- void *addr;
+ pcilib_kmem_handle_t *kmem; /**< the kernel memory for software registers */
+ void *addr; /**< the virtual adress of the allocated kernel memory*/
};
/**
@@ -40,8 +40,10 @@ void pcilib_software_registers_close(pcilib_t *ctx, pcilib_register_bank_context
* @return a bank context with the adress of the kernel space memory related to it
*/
pcilib_register_bank_context_t* pcilib_software_registers_open(pcilib_t *ctx, pcilib_register_bank_t bank, const char* model, const void *args) {
+ int err;
pcilib_software_register_bank_context_t *bank_ctx;
pcilib_kmem_handle_t *handle;
+ pcilib_lock_t *lock;
pcilib_kmem_reuse_state_t reused;
const pcilib_register_bank_description_t *bank_desc = ctx->banks + bank;
@@ -52,9 +54,29 @@ pcilib_register_bank_context_t* pcilib_software_registers_open(pcilib_t *ctx, pc
}
bank_ctx = calloc(1, sizeof(pcilib_software_register_bank_context_t));
+ if (!bank_ctx) {
+ pcilib_error("Memory allocation for bank context has failed");
+ return NULL;
+ }
+
+ lock = pcilib_get_lock(ctx, PCILIB_LOCK_FLAGS_DEFAULT, "softreg/%s", bank_desc->name);
+ if (!lock) {
+ pcilib_error("Failed to initialize a lock to protect bank %s with software registers", bank_desc->name);
+ return NULL;
+ }
+
+ err = pcilib_lock(lock);
+ if (err) {
+ pcilib_return_lock(ctx, PCILIB_LOCK_FLAGS_DEFAULT, lock);
+ pcilib_error("Error (%i) obtaining lock on bank %s with software registers", err, bank_desc->name);
+ return NULL;
+ }
+
handle = pcilib_alloc_kernel_memory(ctx, PCILIB_KMEM_TYPE_PAGE, 1, PCILIB_KMEM_PAGE_SIZE, 0, PCILIB_KMEM_USE(PCILIB_KMEM_USE_SOFTWARE_REGISTERS, bank_desc->addr), PCILIB_KMEM_FLAG_REUSE|PCILIB_KMEM_FLAG_PERSISTENT);
if (!handle) {
+ pcilib_unlock(lock);
+ pcilib_return_lock(ctx, PCILIB_LOCK_FLAGS_DEFAULT, lock);
pcilib_error("Allocation of kernel memory for software registers has failed");
pcilib_software_registers_close(ctx, (pcilib_register_bank_context_t*)bank_ctx);
return NULL;
@@ -68,6 +90,8 @@ pcilib_register_bank_context_t* pcilib_software_registers_open(pcilib_t *ctx, pc
pcilib_register_t i;
if (reused & PCILIB_KMEM_REUSE_PARTIAL) {
+ pcilib_unlock(lock);
+ pcilib_return_lock(ctx, PCILIB_LOCK_FLAGS_DEFAULT, lock);
pcilib_error("Inconsistent software registers are found (only part of required buffers is available)");
pcilib_software_registers_close(ctx, (pcilib_register_bank_context_t*)bank_ctx);
return NULL;
@@ -80,6 +104,9 @@ pcilib_register_bank_context_t* pcilib_software_registers_open(pcilib_t *ctx, pc
}
}
+ pcilib_unlock(lock);
+ pcilib_return_lock(ctx, PCILIB_LOCK_FLAGS_DEFAULT, lock);
+
return (pcilib_register_bank_context_t*)bank_ctx;
}
@@ -97,7 +124,8 @@ int pcilib_software_registers_read(pcilib_t *ctx, pcilib_register_bank_context_t
pcilib_error("Trying to access space outside of the define register bank (bank: %s, addr: 0x%lx)", bank_ctx->bank->name, addr);
return PCILIB_ERROR_INVALID_ADDRESS;
}
-
+
+ // we consider this atomic operation and, therefore, do no locking
*value = *(pcilib_register_value_t*)(((pcilib_software_register_bank_context_t*)bank_ctx)->addr + addr);
return 0;
}
@@ -111,12 +139,13 @@ int pcilib_software_registers_read(pcilib_t *ctx, pcilib_register_bank_context_t
* @param[out] value the value we want to write in the register
* @return 0 in case of success
*/
-int pcilib_software_registers_write(pcilib_t *ctx, pcilib_register_bank_context_t *bank_ctx, pcilib_register_addr_t addr, pcilib_register_value_t value){
+int pcilib_software_registers_write(pcilib_t *ctx, pcilib_register_bank_context_t *bank_ctx, pcilib_register_addr_t addr, pcilib_register_value_t value) {
if ((addr + sizeof(pcilib_register_value_t)) > bank_ctx->bank->size) {
pcilib_error("Trying to access space outside of the define register bank (bank: %s, addr: 0x%lx)", bank_ctx->bank->name, addr);
return PCILIB_ERROR_INVALID_ADDRESS;
}
+ // we consider this atomic operation and, therefore, do no locking
*(pcilib_register_value_t*)(((pcilib_software_register_bank_context_t*)bank_ctx)->addr + addr) = value;
return 0;
}
--
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