public inbox for newlib-cvs@sourceware.org
help / color / mirror / Atom feed
* [newlib-cygwin] ARM/AArch64: Fix GetCmdLine semihosting directives
@ 2017-05-19 19:45 Jeff Johnston
0 siblings, 0 replies; only message in thread
From: Jeff Johnston @ 2017-05-19 19:45 UTC (permalink / raw)
To: newlib-cvs
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=9b1167219a11311dd5a3db4b6802feea2f2ee765
commit 9b1167219a11311dd5a3db4b6802feea2f2ee765
Author: Laurent ALFONSI <laurent.alfonsi@st.com>
Date: Tue Apr 18 17:50:16 2017 +0200
ARM/AArch64: Fix GetCmdLine semihosting directives
When simulating arm code, the target program startup code (crt0) uses
semihosting invocations to get the command line from the simulator. The
simulator returns the command line and its size into the area passed in
parameter. (ARM 32-bit specifications :
http://infocenter.arm.com/help/topic/com.arm.doc.dui0058d/DUI0058.pdf
chapter "5.4.19 SYS_GET_CMDLINE").
The memory area pointed by the semihosting register argument is located
in .text section (usually not writtable (RX)).
If we run this code on a simulator that respects this rights properties
(qemu user-mode for instance), the command line will not be written to
the .text program memory, in particular the length of the string. The
program runs with an empty command line. This problem hasn't been seen
earlier probably because qemu user-mode is not so much used, but this can
happen with another simulator that refuse to write in a read-only segment.
With this modification, the command line can be correctly passed to the
target program.
Changes:
- libgloss/arm/crt0.S : Arguments passed to the AngelSWI_Reason_GetCmdLine
semihosting invocation are placed into .data section instead of .text
- libgloss/aarch64/crt0.S : Idem for aarch64 AngelSVC_Reason_GetCmdLine
semihosting.
Diff:
---
libgloss/aarch64/crt0.S | 10 ++++++----
libgloss/arm/crt0.S | 9 ++++++---
2 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/libgloss/aarch64/crt0.S b/libgloss/aarch64/crt0.S
index ae6264d..ed4dafc 100644
--- a/libgloss/aarch64/crt0.S
+++ b/libgloss/aarch64/crt0.S
@@ -156,10 +156,11 @@
bl FUNCTION (_init)
/* Fetch and parse the command line. */
- adr x1, .Lcmdline /* Command line descriptor. */
+ ldr x1, .Lcmdline /* Command line descriptor. */
mov w0, #AngelSVC_Reason_GetCmdLine
AngelSVCAsm AngelSVC
ldr x8, .Lcmdline
+ ldr x8, [x8]
mov x0, #0 /* argc */
mov x1, sp /* argv */
@@ -239,9 +240,7 @@ FUNCTION (_cpu_init_hook):
.Lenvp:
GEN_DWORD env
.Lcmdline:
- GEN_DWORD CommandLine
- .dword 255
-
+ GEN_DWORD AngelSVCArgs
/* Workspace for Angel calls. */
.data
.align 3
@@ -258,3 +257,6 @@ StackBase: .dword 0
StackLimit: .dword 0
env: .dword 0 /* Dummy environment array */
CommandLine: .space 256,0 /* Maximum length of 255 chars handled. */
+AngelSVCArgs:
+ GEN_DWORD CommandLine
+ .dword 255
diff --git a/libgloss/arm/crt0.S b/libgloss/arm/crt0.S
index 35c306b..48f3d6b 100644
--- a/libgloss/arm/crt0.S
+++ b/libgloss/arm/crt0.S
@@ -296,9 +296,10 @@ __change_mode:
movs r1, r0
#else
movs r0, #AngelSWI_Reason_GetCmdLine
- adr r1, .LC30 /* Space for command line */
+ ldr r1, .LC30 /* Space for command line */
AngelSWIAsm AngelSWI
ldr r1, .LC30
+ ldr r1, [r1]
#endif
/* Parse string at r1 */
movs r0, #0 /* count of arguments so far */
@@ -505,8 +506,7 @@ change_back:
#endif
#ifdef ARM_RDI_MONITOR
.LC30:
- .word CommandLine
- .word 255
+ .word AngelSWIArgs
.LC31:
.word __end__
@@ -519,6 +519,9 @@ HeapLimit: .word 0
__stack_base__: .word 0
StackLimit: .word 0
CommandLine: .space 256,0 /* Maximum length of 255 chars handled. */
+AngelSWIArgs:
+ .word CommandLine
+ .word 255
#endif
#ifdef __pe__
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2017-05-19 19:45 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-05-19 19:45 [newlib-cygwin] ARM/AArch64: Fix GetCmdLine semihosting directives Jeff Johnston
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).