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Message-Id: <20240827-patches-below_hint_mmap-v1-12-46ff2eb9022d@rivosinc.com>
Date: Tue, 27 Aug 2024 22:49:18 -0700
From: Charlie Jenkins <charlie@...osinc.com>
To: Arnd Bergmann <arnd@...db.de>, Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>,
Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>,
Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Naveen N Rao <naveen@...nel.org>, Muchun Song <muchun.song@...ux.dev>,
Andrew Morton <akpm@...ux-foundation.org>,
"Liam R. Howlett" <Liam.Howlett@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>,
Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
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x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
Huacai Chen <chenhuacai@...nel.org>, WANG Xuerui <kernel@...0n.name>,
Russell King <linux@...linux.org.uk>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
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Yoshinori Sato <ysato@...rs.sourceforge.jp>, Rich Felker <dalias@...c.org>,
John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>,
"David S. Miller" <davem@...emloft.net>,
Andreas Larsson <andreas@...sler.com>, Shuah Khan <shuah@...nel.org>,
Alexandre Ghiti <alexghiti@...osinc.com>
Cc: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org,
Palmer Dabbelt <palmer@...osinc.com>, linux-riscv@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, linuxppc-dev@...ts.ozlabs.org,
linux-mm@...ck.org, loongarch@...ts.linux.dev, linux-mips@...r.kernel.org,
linux-parisc@...r.kernel.org, linux-s390@...r.kernel.org,
linux-sh@...r.kernel.org, sparclinux@...r.kernel.org,
linux-kselftest@...r.kernel.org, Charlie Jenkins <charlie@...osinc.com>
Subject: [PATCH 12/16] parisc: mm: Support MAP_BELOW_HINT
Add support for MAP_BELOW_HINT to mmap by restricting high_limit to addr
when the flag is enabled.
Signed-off-by: Charlie Jenkins <charlie@...osinc.com>
---
arch/parisc/include/uapi/asm/mman.h | 1 +
arch/parisc/kernel/sys_parisc.c | 9 +++++++++
tools/arch/parisc/include/uapi/asm/mman.h | 1 +
3 files changed, 11 insertions(+)
diff --git a/arch/parisc/include/uapi/asm/mman.h b/arch/parisc/include/uapi/asm/mman.h
index 68c44f99bc93..44925ef8ac44 100644
--- a/arch/parisc/include/uapi/asm/mman.h
+++ b/arch/parisc/include/uapi/asm/mman.h
@@ -26,6 +26,7 @@
#define MAP_HUGETLB 0x80000 /* create a huge page mapping */
#define MAP_FIXED_NOREPLACE 0x100000 /* MAP_FIXED which doesn't unmap underlying mapping */
#define MAP_UNINITIALIZED 0 /* uninitialized anonymous mmap */
+#define MAP_BELOW_HINT 0x200000 /* give out address that is below (inclusive) hint address */
#define MS_SYNC 1 /* synchronous memory sync */
#define MS_ASYNC 2 /* sync memory asynchronously */
diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index f7722451276e..feccb60cf746 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -148,6 +148,13 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.low_limit = PAGE_SIZE;
info.high_limit = mm->mmap_base;
+ if (flags & MAP_BELOW_HINT)
+ /*
+ * Subtract (STACK_TOP - mm->mmap_base) to get random
+ * offset defined in mmap_base() in mm/util.c
+ */
+ info.high_limit = MIN(info.high_limit,
+ (addr + len) - (STACK_TOP - mm->mmap_base));
addr = vm_unmapped_area(&info);
if (!(addr & ~PAGE_MASK))
return addr;
@@ -163,6 +170,8 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
info.low_limit = mm->mmap_base;
info.high_limit = mmap_upper_limit(NULL);
+ if (flags & MAP_BELOW_HINT)
+ info.high_limit = MIN(info.high_limit, addr + len);
return vm_unmapped_area(&info);
}
diff --git a/tools/arch/parisc/include/uapi/asm/mman.h b/tools/arch/parisc/include/uapi/asm/mman.h
index 4cc88a642e10..297acc0f7b2a 100644
--- a/tools/arch/parisc/include/uapi/asm/mman.h
+++ b/tools/arch/parisc/include/uapi/asm/mman.h
@@ -40,4 +40,5 @@
/* MAP_32BIT is undefined on parisc, fix it for perf */
#define MAP_32BIT 0
#define MAP_UNINITIALIZED 0
+#define MAP_BELOW_MAP 0x200000
#endif
--
2.45.0
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