Changeset 5a5269d in mainline for kernel/arch/amd64

Timestamp:

2019-07-02T12:03:55Z (6 years ago)

Author:

GitHub <noreply@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

98c4c16

Parents:

aca97582

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2019-07-02 12:03:55)

git-committer:

GitHub <noreply@…> (2019-07-02 12:03:55)

Message:

Change type of uspace pointers in kernel from pointer type to numeric (#170)

From kernel's perspective, userspace addresses are not valid pointers,
and can only be used in calls to copy_to/from_uspace().
Therefore, we change the type of those arguments and variables to
uspace_addr_t which is an alias for sysarg_t.

This allows the compiler to catch accidental direct accesses to
userspace addresses.

Additionally, to avoid losing the type information in code,
a macro uspace_ptr(type) is used that translates to uspace_addr_t.
I makes no functional difference, but allows keeping the type information
in code in case we implement some sort of static checking for it in the future.

However, ccheck doesn't like that, so instead of using uspace_ptr(char),
we use uspace_ptr_char which is defined as
#define uspace_ptr_char uspace_ptr(char).

Location:

kernel/arch/amd64/src

Files:

• debug/stacktrace.c (modified) (1 diff)
• userspace.c (modified) (1 diff)

kernel/arch/amd64/src/debug/stacktrace.c

@@ -69 +69 @@
 bool uspace_frame_pointer_prev(stack_trace_context_t *ctx, uintptr_t *prev)
 {
-        return !copy_from_uspace((void *) prev,
-            (uint64_t *) ctx->fp + FRAME_OFFSET_FP_PREV, sizeof(*prev));
+        return !copy_from_uspace(prev,
+            ctx->fp + sizeof(uintptr_t) * FRAME_OFFSET_FP_PREV, sizeof(*prev));
 }
 
 bool uspace_return_address_get(stack_trace_context_t *ctx, uintptr_t *ra)
 {
-        return !copy_from_uspace((void *) ra,
-            (uint64_t *) ctx->fp + FRAME_OFFSET_RA, sizeof(*ra));
+        return !copy_from_uspace(ra,
+            ctx->fp + sizeof(uintptr_t) * FRAME_OFFSET_RA, sizeof(*ra));
 }
 

kernel/arch/amd64/src/userspace.c

@@ -66 +66 @@
             "iretq\n"
             :: [udata_des] "i" (GDT_SELECTOR(UDATA_DES) | PL_USER),
-              [stack_top] "r" ((uint8_t *) kernel_uarg->uspace_stack +
+              [stack_top] "r" (kernel_uarg->uspace_stack +
               kernel_uarg->uspace_stack_size),
               [rflags] "r" (rflags),