Re: [PATCH] sim: or1k: Eliminate dangerous RWX load segments

Re: [PATCH] sim: or1k: Eliminate dangerous RWX load segments

[Nick Clifton]

Hi Stafford Horne,

   The simulator code is actually maintained by the GNU GDB project
   rather than the GNU Binutils project, so I am redirecting this
   email to the gdb-patches list.

> This fixes test failures caused by the new linker warning which report:
> 
>    ./ld/ld-new: warning: load.S.x has a LOAD segment with RWX permissions
> 
> Fix this by splitting the linker MEMORY into ram and rom to avoid
> generating RWX sections.  This required tests to be adjusted to fix
> issues with the move.  Namely:
> 
>    - fpu tests: were incorrectly using l.ori with ha(anchor) which now
>      that we pushed the anchor up in memory it exposes the bug.  Update
>      to used the correct l.movhi instruction instead.
>    - adrp test: the test reports ram offset addresses, now that we have
>      moved memory layout around a bit I adjusted the test output.  Some
>      padding is added before pi to show that the actual address of pi and
>      the adrp page offset are not the same.

(It is nice to see that this new linker feature helped to detect these problems. :-)

> Bug: https://sourceware.org/PR29957
> ---
>   sim/testsuite/or1k/adrp.S               | 5 +++--
>   sim/testsuite/or1k/fpu-unordered.S      | 2 +-
>   sim/testsuite/or1k/fpu64a32-unordered.S | 2 +-
>   sim/testsuite/or1k/fpu64a32.S           | 2 +-
>   sim/testsuite/or1k/or1k-test.ld         | 7 ++++---
>   5 files changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/sim/testsuite/or1k/adrp.S b/sim/testsuite/or1k/adrp.S
> index eaddcb03885..192324c698e 100644
> --- a/sim/testsuite/or1k/adrp.S
> +++ b/sim/testsuite/or1k/adrp.S
> @@ -17,9 +17,9 @@
>   
>   # mach: or1k
>   # output: report(0x00002064);\n
> -# output: report(0x00012138);\n
> +# output: report(0x0001a008);\n
>   # output: report(0x00002000);\n
> -# output: report(0x00012000);\n
> +# output: report(0x0001a000);\n
>   # output: report(0x00002000);\n
>   # output: report(0x00014000);\n
>   # output: report(0x00000000);\n
> @@ -32,6 +32,7 @@
>   	.section .data
>   	.org 0x10000
>   	.align 4
> +pad:	.quad 	0
>   	.type   pi, @object
>   	.size   pi, 4
>   pi:
> diff --git a/sim/testsuite/or1k/fpu-unordered.S b/sim/testsuite/or1k/fpu-unordered.S
> index 624aa0fe05d..a89172e37af 100644
> --- a/sim/testsuite/or1k/fpu-unordered.S
> +++ b/sim/testsuite/or1k/fpu-unordered.S
> @@ -57,7 +57,7 @@ start_tests:
>   	 *  r13  e   as float
>   	 *  r16  nan as float
>   	 */
> -	l.ori	r11, r0, ha(anchor)
> +	l.movhi	r11, ha(anchor)
>   	l.addi	r11, r11, lo(anchor)
>   	l.lwz	r12, 0(r11)
>   
> diff --git a/sim/testsuite/or1k/fpu64a32-unordered.S b/sim/testsuite/or1k/fpu64a32-unordered.S
> index e0ae6e770d1..51d915e4e75 100644
> --- a/sim/testsuite/or1k/fpu64a32-unordered.S
> +++ b/sim/testsuite/or1k/fpu64a32-unordered.S
> @@ -58,7 +58,7 @@ start_tests:
>   	 *  r14,r15  e   as double
>   	 *  r16,r17  nan as double
>   	 */
> -	l.ori	r11, r0, ha(anchor)
> +	l.movhi	r11, ha(anchor)
>   	l.addi	r11, r11, lo(anchor)
>   	l.lwz	r12, 0(r11)
>   	l.lwz	r13, 4(r11)
> diff --git a/sim/testsuite/or1k/fpu64a32.S b/sim/testsuite/or1k/fpu64a32.S
> index 71b72b7761c..6ea60b28cf2 100644
> --- a/sim/testsuite/or1k/fpu64a32.S
> +++ b/sim/testsuite/or1k/fpu64a32.S
> @@ -98,7 +98,7 @@ start_tests:
>   	 *  r14,r15  e  as double
>   	 *  r16,r17  a long long
>   	 */
> -	l.ori	r11, r0, ha(anchor)
> +	l.movhi	r11, ha(anchor)
>   	l.addi	r11, r11, lo(anchor)
>   	l.lwz	r12, 0(r11)
>   	l.lwz	r13, 4(r11)
> diff --git a/sim/testsuite/or1k/or1k-test.ld b/sim/testsuite/or1k/or1k-test.ld
> index f1535daeabd..c26ecaf3f23 100644
> --- a/sim/testsuite/or1k/or1k-test.ld
> +++ b/sim/testsuite/or1k/or1k-test.ld
> @@ -20,8 +20,9 @@ MEMORY
>       /* The exception vectors actually start at 0x100, but if you specify
>          that address here, the "--output-target binary" step will start from
>          address 0 with the contents meant for address 0x100.  */
> -    exception_vectors : ORIGIN =  0 , LENGTH = 8K
> -    ram               : ORIGIN =  8K, LENGTH = 2M - 8K
> +    exception_vectors : ORIGIN =  0 , LENGTH =  8K
> +    rom               : ORIGIN =  8K, LENGTH = 40K
> +    ram               : ORIGIN = 40K, LENGTH =  2M - 40K
>   }
>   
>   SECTIONS
> @@ -37,7 +38,7 @@ SECTIONS
>   	*(.text.*)
>   	*(.rodata)
>   	*(.rodata.*)
> -    } > ram
> +    } > rom
>   
>       .data :
>       {