From: Helge Deller <deller@gmx.de>
Date: Sat, 24 Sep 2022 11:44:58 +0000 (+0200)
Subject: linux-user/hppa: Drop stack guard page on hppa target
X-Git-Tag: v7.2.0-rc0~69^2~16
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f43882052f330ce5f5a1a2553466df5aa0808fa0;p=thirdparty%2Fqemu.git

linux-user/hppa: Drop stack guard page on hppa target

The stack-overflow check when building the "grep" debian package fails
on the debian hppa target. Reason is, that the guard page at the top
of the stack (which is added by qemu) prevents the fault handler in the
grep program to properly detect the stack overflow.

The Linux kernel on a physical machine doesn't install a guard page
either, so drop it and as such fix the build of "grep".

Signed-off-by: Helge Deller <deller@gmx.de>
Message-Id: <20220924114501.21767-5-deller@gmx.de>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index ba5c4c02e59..c7e3f1d47c1 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2096,9 +2096,15 @@ static abi_ulong setup_arg_pages(struct linux_binprm *bprm,
     if (size < STACK_LOWER_LIMIT) {
         size = STACK_LOWER_LIMIT;
     }
-    guard = TARGET_PAGE_SIZE;
-    if (guard < qemu_real_host_page_size()) {
-        guard = qemu_real_host_page_size();
+
+    if (STACK_GROWS_DOWN) {
+        guard = TARGET_PAGE_SIZE;
+        if (guard < qemu_real_host_page_size()) {
+            guard = qemu_real_host_page_size();
+        }
+    } else {
+        /* no guard page for hppa target where stack grows upwards. */
+        guard = 0;
     }
 
     prot = PROT_READ | PROT_WRITE;
@@ -2118,7 +2124,6 @@ static abi_ulong setup_arg_pages(struct linux_binprm *bprm,
         info->stack_limit = error + guard;
         return info->stack_limit + size - sizeof(void *);
     } else {
-        target_mprotect(error + size, guard, PROT_NONE);
         info->stack_limit = error + size;
         return error;
     }