- 05 Sep, 2005 40 commits
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Bodo Stroesser authored
With this patch, we change the way we handle switching from PTRACE_SYSEMU to PTRACE_{SINGLESTEP,SYSCALL}, to free TIF_SYSCALL_EMU from double use as a preparation for PTRACE_SYSEMU_SINGLESTEP extension, without changing the behavior of the host kernel. Signed-off-by:Bodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by:
Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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Laurent Vivier authored
Jeff Dike <jdike@addtoit.com>, Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>, Bodo Stroesser <bstroesser@fujitsu-siemens.com> Adds a new ptrace(2) mode, called PTRACE_SYSEMU, resembling PTRACE_SYSCALL except that the kernel does not execute the requested syscall; this is useful to improve performance for virtual environments, like UML, which want to run the syscall on their own. In fact, using PTRACE_SYSCALL means stopping child execution twice, on entry and on exit, and each time you also have two context switches; with SYSEMU you avoid the 2nd stop and so save two context switches per syscall. Also, some architectures don't have support in the host for changing the syscall number via ptrace(), which is currently needed to skip syscall execution (UML turns any syscall into getpid() to avoid it being executed on the host). Fixing that is hard, while SYSEMU is easier to implement. * This version of the patch includes some suggestions of Jeff Dike to avoid adding any instructions to the syscall fast path, plus some other little changes, by myself, to make it work even when the syscall is executed with SYSENTER (but I'm unsure about them). It has been widely tested for quite a lot of time. * Various fixed were included to handle the various switches between various states, i.e. when for instance a syscall entry is traced with one of PT_SYSCALL / _SYSEMU / _SINGLESTEP and another one is used on exit. Basically, this is done by remembering which one of them was used even after the call to ptrace_notify(). * We're combining TIF_SYSCALL_EMU with TIF_SYSCALL_TRACE or TIF_SINGLESTEP to make do_syscall_trace() notice that the current syscall was started with SYSEMU on entry, so that no notification ought to be done in the exit path; this is a bit of a hack, so this problem is solved in another way in next patches. * Also, the effects of the patch: "Ptrace - i386: fix Syscall Audit interaction with singlestep" are cancelled; they are restored back in the last patch of this series. Detailed descriptions of the patches doing this kind of processing follow (but I've already summed everything up). * Fix behaviour when changing interception kind #1. In do_syscall_trace(), we check the status of the TIF_SYSCALL_EMU flag only after doing the debugger notification; but the debugger might have changed the status of this flag because he continued execution with PTRACE_SYSCALL, so this is wrong. This patch fixes it by saving the flag status before calling ptrace_notify(). * Fix behaviour when changing interception kind #2: avoid intercepting syscall on return when using SYSCALL again. A guest process switching from using PTRACE_SYSEMU to PTRACE_SYSCALL crashes. The problem is in arch/i386/kernel/entry.S. The current SYSEMU patch inhibits the syscall-handler to be called, but does not prevent do_syscall_trace() to be called after this for syscall completion interception. The appended patch fixes this. It reuses the flag TIF_SYSCALL_EMU to remember "we come from PTRACE_SYSEMU and now are in PTRACE_SYSCALL", since the flag is unused in the depicted situation. * Fix behaviour when changing interception kind #3: avoid intercepting syscall on return when using SINGLESTEP. When testing 2.6.9 and the skas3.v6 patch, with my latest patch and had problems with singlestepping on UML in SKAS with SYSEMU. It looped receiving SIGTRAPs without moving forward. EIP of the traced process was the same for all SIGTRAPs. What's missing is to handle switching from PTRACE_SYSCALL_EMU to PTRACE_SINGLESTEP in a way very similar to what is done for the change from PTRACE_SYSCALL_EMU to PTRACE_SYSCALL_TRACE. I.e., after calling ptrace(PTRACE_SYSEMU), on the return path, the debugger is notified and then wake ups the process; the syscall is executed (or skipped, when do_syscall_trace() returns 0, i.e. when using PTRACE_SYSEMU), and do_syscall_trace() is called again. Since we are on the return path of a SYSEMU'd syscall, if the wake up is performed through ptrace(PTRACE_SYSCALL), we must still avoid notifying the parent of the syscall exit. Now, this behaviour is extended even to resuming with PTRACE_SINGLESTEP. Signed-off-by: -
Bodo Stroesser authored
Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Avoid giving two traps for singlestep instead of one, when syscall auditing is enabled. In fact no singlestep trap is sent on syscall entry, only on syscall exit, as can be seen in entry.S: # Note that in this mask _TIF_SINGLESTEP is not tested !!! <<<<<<<<<<<<<< testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),TI_flags(%ebp) jnz syscall_trace_entry ... syscall_trace_entry: ... call do_syscall_trace But auditing a SINGLESTEP'ed process causes do_syscall_trace to be called, so the tracer will get one more trap on the syscall entry path, which it shouldn't. Signed-off-by: -
Jeff Dike authored
To the extent that sub-Kconfig files exist elsewhere in the tree, they are named Kconfig.foo, rather than the Kconfig_foo that UML has. This patch brings the names in line with the rest of the tree. Signed-off-by:
Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by:
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Jeff Dike authored
This eliminates the segfault info ring buffer, which added a system call to each page fault, and which hadn't been useful for debugging in ages. Signed-off-by:
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Adrian Bunk authored
This patch converts arch/cris/Kconfig.debug to using lib/Kconfig.debug. This should fix a compile error in 2.6.13-rc4 caused by a missing CONFIG_LOG_BUF_SHIFT definition. While I was editing this file, I also converted some spaces to tabs. Signed-off-by:
Adrian Bunk <bunk@stusta.de> Acked-by:
Mikael Starvik <starvik@axis.com> Signed-off-by:
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Roman Zippel authored
Use the builtin functions for memset/memclr/memcpy, special optimizations for page operations have dedicated functions now. Uninline memmove/memchr and move all functions into a single file and clean it up a little. Signed-off-by:
Roman Zippel <zippel@linux-m68k.org> Signed-off-by:
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Roman Zippel authored
Move a few cache functions into its own file and fix flush_icache_range() so it can handle both kernel and user addresses correctly (assuming context is set correctly). Turn copy_to_user_page/copy_from_user_page into inline functions and add a missing cache flush. Signed-off-by:
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Roman Zippel authored
- create helper function singlestep_disable() - move variable definitions to the top of the function - use "out_eio" label as common error destination - don't clear failure value for PTRACE_SETREGS/PTRACE_GETREGS Signed-off-by:
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Roman Zippel authored
This reformats and properly indents sys_ptrace (only whitespace changes). Signed-off-by:
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Shaohua Li authored
The timers lack .suspend/.resume methods. Because of this, jiffies got a big compensation after a S3 resume. And then softlockup watchdog reports an oops. This occured with HPET enabled, but it's also possible for other timers. Signed-off-by:
Shaohua Li <shaohua.li@intel.com> Signed-off-by:
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Pavel Machek authored
Clean code up a bit, and only show suspend to disk as available when it is configured in. Signed-off-by:
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Pavel Machek authored
If process freezing fails, some processes are frozen, and rest are left in "were asked to be frozen" state. Thats wrong, we should leave it in some consistent state. Signed-off-by:
Pavel Machek <pavel@suse.cz> Signed-off-by:
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Pavel Machek authored
Drop printing during normal boot (when no image exists in swap), print message when drivers fail, fix error paths and consolidate near-identical functions in disk.c (and functions with just one statement). Signed-off-by:
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Shaohua Li authored
It is trying to protect swsusp_resume_device and software_resume() from two users banging it from userspace at the same time. Signed-off-by:
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Andreas Steinmetz authored
The attached patch contains a mini howto for using dm-crypt together with swsusp. Signed-off-by:
Andreas Steinmetz <ast@domdv.de> Signed-off-by:
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Michal Schmidt authored
The function calc_nr uses an iterative algorithm to calculate the number of pages needed for the image and the pagedir. Exactly the same result can be obtained with a one-line expression. Note that this was even proved correct ;-). Signed-off-by:
Michal Schmidt <xschmi00@stud.feec.vutbr.cz> Signed-off-by:
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Michal Schmidt authored
Stop the disks from spinning down and up on suspend. Signed-off-by:
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Andreas Steinmetz authored
The patch protects from leaking sensitive data after resume from suspend. During suspend a temporary key is created and this key is used to encrypt the data written to disk. When, during resume, the data was read back into memory the temporary key is destroyed which simply means that all data written to disk during suspend are then inaccessible so they can't be stolen lateron. Think of the following: you suspend while an application is running that keeps sensitive data in memory. The application itself prevents the data from being swapped out. Suspend, however, must write these data to swap to be able to resume lateron. Without suspend encryption your sensitive data are then stored in plaintext on disk. This means that after resume your sensitive data are accessible to all applications having direct access to the swap device which was used for suspend. If you don't need swap after resume these data can remain on disk virtually forever. Thus it can happen that your system gets broken in weeks later and sensitive data which you thought were encrypted and protected are retrieved and stolen from the swap device. Signed-off-by:
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Pavel Machek authored
This should bits from -mm tree that are affected by pm_message_t conversion. [I'm not 100% sure I got all of them, but I certainly got all the errors on make allyesconfig build, and most of warnings, too. I'll go through the buildlog tommorow and fix any remaining bits]. Signed-off-by:
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Pavel Machek authored
This adds type-checking to pm_message_t, so that people can't confuse it with int or u32. It also allows us to fix "disk yoyo" during suspend (disk spinning down/up/down). [We've tried that before; since that cpufreq problems were fixed and I've tried make allyes config and fixed resulting damage.] Signed-off-by:
Alexander Nyberg <alexn@telia.com> Signed-off-by:
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Pavel Machek authored
Fix remaining bits of u32 vs. pm_message confusion. Should not break anything. Signed-off-by:
Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by:
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Pavel Machek authored
Update suspend documentation. Signed-off-by:
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Pierre Ossman authored
Reset the ISA DMA controller into a known state after a suspend. Primary concern was reenabling the cascading DMA channel (4). Signed-off-by:
Pierre Ossman <drzeus@drzeus.cx> Cc: Andi Kleen <ak@muc.de> Signed-off-by:
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Pierre Ossman authored
Reset the ISA DMA controller into a known state after a suspend. Primary concern was reenabling the cascading DMA channel (4). Signed-off-by:
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Pavel Machek authored
This should make refrigerator sleep properly, not busywait after the first schedule() returns. Signed-off-by:
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Benjamin LaHaise authored
This patch moves the common code in x86 and x86-64's semaphore.c into a single file in lib/semaphore-sleepers.c. The arch specific asm stubs are left in the arch tree (in semaphore.c for i386 and in the asm for x86-64). There should be no changes in code/functionality with this patch. Signed-off-by:
Benjamin LaHaise <benjamin.c.lahaise@intel.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by:
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Zwane Mwaikambo authored
for_each_cpu walks through all processors in cpu_possible_map, which is defined as cpu_callout_map on i386 and isn't initialised until all processors have been booted. This breaks things which do for_each_cpu iterations early during boot. So, define cpu_possible_map as a bitmap with NR_CPUS bits populated. This was triggered by a patch i'm working on which does alloc_percpu before bringing up secondary processors. From: Alexander Nyberg <alexn@telia.com> i386-boottime-for_each_cpu-broken.patch i386-boottime-for_each_cpu-broken-fix.patch The SMP version of __alloc_percpu checks the cpu_possible_map before allocating memory for a certain cpu. With the above patches the BSP cpuid is never set in cpu_possible_map which breaks CONFIG_SMP on uniprocessor machines (as soon as someone tries to dereference something allocated via __alloc_percpu, which in fact is never allocated since the cpu is not set in cpu_possible_map). Signed-off-by:
Zwane Mwaikambo <zwane@arm.linux.org.uk> Signed-off-by:
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Zachary Amsden authored
Add a clone operation for pgd updates. This helps complete the encapsulation of updates to page tables (or pages about to become page tables) into accessor functions rather than using memcpy() to duplicate them. This is both generally good for consistency and also necessary for running in a hypervisor which requires explicit updates to page table entries. The new function is: clone_pgd_range(pgd_t *dst, pgd_t *src, int count); dst - pointer to pgd range anwhere on a pgd page src - "" count - the number of pgds to copy. dst and src can be on the same page, but the range must not overlap and must not cross a page boundary. Note that I ommitted using this call to copy pgd entries into the software suspend page root, since this is not technically a live paging structure, rather it is used on resume from suspend. CC'ing Pavel in case he has any feedback on this. Thanks to Chris Wright for noticing that this could be more optimal in PAE compiles by eliminating the memset. Signed-off-by:
Zachary Amsden <zach@vmware.com> Signed-off-by:
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George Anzinger authored
This patch adds a notify to the die_nmi notify that the system is about to be taken down. If the notify is handled with a NOTIFY_STOP return, the system is given a new lease on life. We also change the nmi watchdog to carry on if die_nmi returns. This give debug code a chance to a) catch watchdog timeouts and b) possibly allow the system to continue, realizing that the time out may be due to debugger activities such as single stepping which is usually done with "other" cpus held. Signed-off-by: George Anzinger<george@mvista.com> Cc: Keith Owens <kaos@ocs.com.au> Signed-off-by:
George Anzinger <george@mvista.com> Signed-off-by:
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Zachary Amsden authored
Introduce a write acessor for updating the current LDT. This is required for hypervisors like Xen that do not allow LDT pages to be directly written. Testing - here's a fun little LDT test that can be trivially modified to test limits as well. /* * Copyright (c) 2005, Zachary Amsden (zach@vmware.com) * This is licensed under the GPL. */ #include <stdio.h> #include <signal.h> #include <asm/ldt.h> #include <asm/segment.h> #include <sys/types.h> #include <unistd.h> #include <sys/mman.h> #define __KERNEL__ #include <asm/page.h> void main(void) { struct user_desc desc; char *code; unsigned long long tsc; code = (char *)mmap(0, 8192, PROT_EXEC|PROT_READ|PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); desc.entry_number = 0; desc.base_addr = code; desc.limit = 1; desc.seg_32bit = 1; desc.contents = MODIFY_LDT_CONTENTS_CODE; desc.read_exec_only = 0; desc.limit_in_pages = 1; desc.seg_not_present = 0; desc.useable = 1; if (modify_ldt(1, &desc, sizeof(desc)) != 0) { perror("modify_ldt"); } printf("code base is 0x%08x\n", (unsigned)code); code[0x0ffe] = 0x0f; /* rdtsc */ code[0x0fff] = 0x31; code[0x1000] = 0xcb; /* lret */ __asm__ __volatile("lcall $7,$0xffe" : "=A" (tsc)); printf("TSC is 0x%016llx\n", tsc); } Signed-off-by: -
Zachary Amsden authored
When reviewing GDT updates, I found the code: set_tss_desc(cpu,t); /* This just modifies memory; ... */ per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TSS].b &= 0xfffffdff; This second line is unnecessary, since set_tss_desc() has already cleared the busy bit. Commented disassembly, line 1: c028b8bd: 8b 0c 86 mov (%esi,%eax,4),%ecx c028b8c0: 01 cb add %ecx,%ebx c028b8c2: 8d 0c 39 lea (%ecx,%edi,1),%ecx => %ecx = per_cpu(cpu_gdt_table, cpu) c028b8c5: 8d 91 80 00 00 00 lea 0x80(%ecx),%edx => %edx = &per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TSS] c028b8cb: 66 c7 42 00 73 20 movw $0x2073,0x0(%edx) c028b8d1: 66 89 5a 02 mov %bx,0x2(%edx) c028b8d5: c1 cb 10 ror $0x10,%ebx c028b8d8: 88 5a 04 mov %bl,0x4(%edx) c028b8db: c6 42 05 89 movb $0x89,0x5(%edx) => ((char *)%edx)[5] = 0x89 (equivalent) ((char *)per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TSS])[5] = 0x89 c028b8df: c6 42 06 00 movb $0x0,0x6(%edx) c028b8e3: 88 7a 07 mov %bh,0x7(%edx) c028b8e6: c1 cb 10 ror $0x10,%ebx => other bits Commented disassembly, line 2: c028b8e9: 8b 14 86 mov (%esi,%eax,4),%edx c028b8ec: 8d 04 3a lea (%edx,%edi,1),%eax => %eax = per_cpu(cpu_gdt_table, cpu) c028b8ef: 81 a0 84 00 00 00 ff andl $0xfffffdff,0x84(%eax) => per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TSS].b &= 0xfffffdff; (equivalent) ((char *)per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TSS])[5] &= 0xfd Note that (0x89 & ~0xfd) == 0; i.e, set_tss_desc(cpu,t) has already stored the type field in the GDT with the busy bit clear. Eliminating redundant and obscure code is always a good thing; in fact, I pointed out this same optimization many moons ago in arch/i386/setup.c, back when it used to be called that. Signed-off-by: -
Zachary Amsden authored
The pushf/popf in switch_to are ONLY used to switch IOPL. Making this explicit in C code is more clear. This pushf/popf pair was added as a bugfix for leaking IOPL to unprivileged processes when using sysenter/sysexit based system calls (sysexit does not restore flags). When requesting an IOPL change in sys_iopl(), it is just as easy to change the current flags and the flags in the stack image (in case an IRET is required), but there is no reason to force an IRET if we came in from the SYSENTER path. This change is the minimal solution for supporting a paravirtualized Linux kernel that allows user processes to run with I/O privilege. Other solutions require radical rewrites of part of the low level fault / system call handling code, or do not fully support sysenter based system calls. Unfortunately, this added one field to the thread_struct. But as a bonus, on P4, the fastest time measured for switch_to() went from 312 to 260 cycles, a win of about 17% in the fast case through this performance critical path. Signed-off-by:
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Zachary Amsden authored
Privilege checking cleanup. Originally, these diffs were much greater, but recent cleanups in Linux have already done much of the cleanup. I added some explanatory comments in places where the reasoning behind certain tests is rather subtle. Also, in traps.c, we can skip the user_mode check in handle_BUG(). The reason is, there are only two call chains - one via die_if_kernel() and one via do_page_fault(), both entering from die(). Both of these paths already ensure that a kernel mode failure has happened. Also, the original check here, if (user_mode(regs)) was insufficient anyways, since it would not rule out BUG faults from V8086 mode execution. Saving the %ss segment in show_regs() rather than assuming a fixed value also gives better information about the current kernel state in the register dump. Signed-off-by:
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Zachary Amsden authored
Some more assembler cleanups I noticed along the way. Signed-off-by:
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Ingo Molnar authored
Noticed by Chuck Ebbert: the .ldt entry of the TSS was set up incorrectly. It never mattered since this was a leftover from old times, so remove it. Signed-off-by:
Ingo Molnar <mingo@elte.hu> Signed-off-by:
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Zachary Amsden authored
Also, setting PDPEs in PAE mode does not require atomic operations, since the PDPEs are cached by the processor, and only reloaded on an explicit or implicit reload of CR3. Since the four PDPEs must always be present in an active root, and the kernel PDPE is never updated, we are safe even from SMIs and interrupts / NMIs using task gates (which reload CR3). Actually, much of this is moot, since the user PDPEs are never updated either, and the only usage of task gates is by the doublefault handler. It appears the only place PGDs get updated in PAE mode is in init_low_mappings() / zap_low_mapping() for initial page table creation and recovery from ACPI sleep state, and these sites are safe by inspection. Getting rid of the cmpxchg8b saves code space and 720 cycles in pgd_alloc on P4. Signed-off-by:
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Zachary Amsden authored
Subtle fix: load_TLS has been moved after saving %fs and %gs segments to avoid creating non-reversible segments. This could conceivably cause a bug if the kernel ever needed to save and restore fs/gs from the NMI handler. It currently does not, but this is the safest approach to avoiding fs/gs corruption. SMIs are safe, since SMI saves the descriptor hidden state. Signed-off-by:
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Zachary Amsden authored
GCC can generate better code around descriptor update and access functions when there is not an explicit "eax" register constraint. Testing: You won't boot if this is messed up, since the TSS descriptor will be corrupted. Verified the assembler and booted. Signed-off-by:
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Zachary Amsden authored
i386 inline assembler cleanup. This change encapsulates descriptor and task register management. Also, it is possible to improve assembler generation in two cases; savesegment may store the value in a register instead of a memory location, which allows GCC to optimize stack variables into registers, and MOV MEM, SEG is always a 16-bit write to memory, making the casting in math-emu unnecessary. Signed-off-by:
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