From c5f4e26e7d1ba07875b9b6988b94a6f3c96f7da4 Mon Sep 17 00:00:00 2001 From: Edward Tomasz Napierala Date: Tue, 21 Jan 2020 19:19:02 +0000 Subject: [PATCH] Make linux(4) handle MAP_32BIT. This unbreaks Mono (mono-devel-4.6.2.7+dfsg-1ubuntu1 from Ubuntu Bionic); previously would crash on "amd64_is_imm32" assert. MFC after: 2 weeks Sponsored by: The FreeBSD Foundation --- sys/compat/linux/linux_mmap.c | 7 +++++++ sys/compat/linux/linux_mmap.h | 1 + 2 files changed, 8 insertions(+) diff --git a/sys/compat/linux/linux_mmap.c b/sys/compat/linux/linux_mmap.c index 59f7176d3996..4ec297134455 100644 --- a/sys/compat/linux/linux_mmap.c +++ b/sys/compat/linux/linux_mmap.c @@ -113,6 +113,13 @@ linux_mmap_common(struct thread *td, uintptr_t addr, size_t len, int prot, if (flags & LINUX_MAP_GROWSDOWN) bsd_flags |= MAP_STACK; + /* + * According to the Linux mmap(2) man page, "MAP_32BIT flag + * is ignored when MAP_FIXED is set." + */ + if ((flags & LINUX_MAP_32BIT) && (flags & LINUX_MAP_FIXED) == 0) + bsd_flags |= MAP_32BIT; + /* * PROT_READ, PROT_WRITE, or PROT_EXEC implies PROT_READ and PROT_EXEC * on Linux/i386 if the binary requires executable stack. diff --git a/sys/compat/linux/linux_mmap.h b/sys/compat/linux/linux_mmap.h index a694dc05799d..8dc123526f21 100644 --- a/sys/compat/linux/linux_mmap.h +++ b/sys/compat/linux/linux_mmap.h @@ -39,6 +39,7 @@ #define LINUX_MAP_PRIVATE 0x0002 #define LINUX_MAP_FIXED 0x0010 #define LINUX_MAP_ANON 0x0020 +#define LINUX_MAP_32BIT 0x0040 #define LINUX_MAP_GROWSDOWN 0x0100 #define LINUX_PROT_GROWSDOWN 0x01000000