parisc: add strict copy size checks (v2)

Add CONFIG_DEBUG_STRICT_USER_COPY_CHECKS, copied from the x86
implementation. Tested with 32 and 64bit kernel.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/parisc/Kconfig.debug b/arch/parisc/Kconfig.debug
index bc989e522a04..7305ac8f7f5b 100644
--- a/arch/parisc/Kconfig.debug
+++ b/arch/parisc/Kconfig.debug
@@ -12,4 +12,18 @@ config DEBUG_RODATA
          portion of the kernel code won't be covered by a TLB anymore.
          If in doubt, say "N".
 
+config DEBUG_STRICT_USER_COPY_CHECKS
+        bool "Strict copy size checks"
+        depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
+        ---help---
+          Enabling this option turns a certain set of sanity checks for user
+          copy operations into compile time failures.
+
+          The copy_from_user() etc checks are there to help test if there
+          are sufficient security checks on the length argument of
+          the copy operation, by having gcc prove that the argument is
+          within bounds.
+
+          If unsure, or if you run an older (pre 4.4) gcc, say N.
+
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