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2018-12-21sparc: vdso: Drop implicit common-page-size linker flagndesaulniers@google.com1-1/+1
GNU linker's -z common-page-size's default value is based on the target architecture. arch/sparc/vdso/Makefile sets it to the architecture default, which is implicit and redundant. Drop it. Link: https://lkml.kernel.org/r/20181206191231.192355-1-ndesaulniers@google.com Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-25sparc: Fix VDSO build with older binutils.David S. Miller6-60/+335
Older versions of bintutils do not allow symbol math across different segments on sparc: ==================== Assembler messages: 99: Error: operation combines symbols in different segments ==================== This is controlled by whether or not DIFF_EXPR_OK is defined in gas/config/tc-*.h and for sparc this was not the case until mid-2017. So we have to patch between %stick and %tick another way. Do what powerpc does and emit two versions of the relevant functions, one using %tick and one using %stick, and patch the symbols in the dynamic symbol table. Fixes: 2f6c9bf31a0b ("sparc: Improve VDSO instruction patching.") Reported-by: Meelis Roos <mroos@linux.ee> Tested-by: Meelis Roos <mroos@linux.ee> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22sparc: Several small VDSO vclock_gettime.c improvements.David S. Miller1-4/+4
Almost entirely borrowed from the x86 code. Main improvement is to avoid having to initialize ts->tv_nsec to zero before the sequence loops, by expanding timespec_add_ns(). Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22sparc: Validate VDSO for undefined symbols.David S. Miller2-1/+12
There should be no undefined symbols in the resulting VDSO image(s). On sparc, fixed register usage can result in undefined symbols ending up in the image. To combat this, we do two things: 1) Define current_thread_info() specially when BUILD_DSO. 2) Ignore "#scratch" register undefined symbols in the output. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22sparc: Really use linker with LDFLAGS.David S. Miller1-9/+7
Rather than funneling through CC. Also, use --hash-style=both just like other VDSO architectures and glibc do. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22sparc: Improve VDSO CFLAGS.David S. Miller1-7/+8
Do not set any special register usage options, use the default which is exactly what we should use for userspace code. Make sure we remove the gcc plugin options from the 64-bit build. The 32-bit cflags got it right already. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22sparc: Set DISABLE_BRANCH_PROFILING in VDSO CFLAGS.David S. Miller2-6/+2
Not in vclock_gettime.c itself. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22sparc: Don't bother masking out TICK_PRIV_BIT in VDSO code.David S. Miller1-8/+1
If the TICK_PRIV_BIT was set, we would not be able to read the tick register in user space, which is where this code runs. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22sparc: Inline VDSO gettime code aggressively.David S. Miller1-22/+17
One interesting thing we need to do is stop using __builtin_return_address() in get_vvar_data(). Simply read the %pc register instead. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22sparc: Improve VDSO instruction patching.David S. Miller5-46/+65
The current VDSO patch mechanism has several problems: 1) It assumes how gcc will emit a function, with a register window, an initial save instruction and then immediately the %tick read when compiling vread_tick(). There is no such guarantees, code generation could change at any time, gcc could put a nop between the save and the %tick read, etc. So this is extremely fragile and would fail some day. 2) It disallows us to properly inline vread_tick() into the callers and thus get the best possible code sequences. So fix this to patch properly, with location based annotations. We have to be careful because we cannot do it the way we do patches elsewhere in the kernel. Those use a sequence like: 1: insn .section .whatever_patch, "ax" .word 1b replacement_insn .previous This is a dynamic shared object, so that .word cannot be resolved at build time, and thus cannot be used to execute the patches when the kernel initializes the images. Even trying to use label difference equations doesn't work in the above kind of scheme: 1: insn .section .whatever_patch, "ax" .word . - 1b replacement_insn .previous The assembler complains that it cannot resolve that computation. The issue is that this is contained in an executable section. Borrow the sequence used by x86 alternatives, which is: 1: insn .pushsection .whatever_patch, "a" .word . - 1b, . - 1f .popsection .pushsection .whatever_patch_replacements, "ax" 1: replacement_insn .previous This works, allows us to inline vread_tick() as much as we like, and can be used for arbitrary kinds of VDSO patching in the future. Also, reverse the condition for patching. Most systems are %stick based, so if we only patch on %tick systems the patching code will get little or no testing. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17sparc: vDSO: Silence an uninitialized variable warningDan Carpenter1-1/+3
Smatch complains that "val" would be uninitialized if kstrtoul() fails. Fixes: 9a08862a5d2e ("vDSO for sparc") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17sparc: Fix syscall fallback bugs in VDSO.David S. Miller1-1/+11
First, the trap number for 32-bit syscalls is 0x10. Also, only negate the return value when syscall error is indicated by the carry bit being set. Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-07sparc: vdso: clean-up vdso MakefileMasahiro Yamada1-5/+3
arch/sparc/vdso/Makefile is a replica of arch/x86/entry/vdso/Makefile. Clean-up the Makefile in the same way as I did for x86: - Remove unnecessary export - Put the generated linker script to $(obj)/ instead of $(src)/ - Simplify cmd_vdso2c The corresponding x86 commits are: - 61615faf0a89 ("x86/build/vdso: Remove unnecessary export in Makefile") - 1742ed2088cc ("x86/build/vdso: Put generated linker scripts to $(obj)/") - c5fcdbf15523 ("x86/build/vdso: Simplify 'cmd_vdso2c'") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-04-07kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markersMasahiro Yamada1-3/+1
GNU Make automatically deletes intermediate files that are updated in a chain of pattern rules. Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts Example 2) %.o <- %.c <- %.c_shipped A couple of makefiles mark such targets as .PRECIOUS to prevent Make from deleting them, but the correct way is to use .SECONDARY. .SECONDARY Prerequisites of this special target are treated as intermediate files but are never automatically deleted. .PRECIOUS When make is interrupted during execution, it may delete the target file it is updating if the file was modified since make started. If you mark the file as precious, make will never delete the file if interrupted. Both can avoid deletion of intermediate files, but the difference is the behavior when Make is interrupted; .SECONDARY deletes the target, but .PRECIOUS does not. The use of .PRECIOUS is relatively rare since we do not want to keep partially constructed (possibly corrupted) targets. Another difference is that .PRECIOUS works with pattern rules whereas .SECONDARY does not. .PRECIOUS: $(obj)/%.lex.c works, but .SECONDARY: $(obj)/%.lex.c has no effect. However, for the reason above, I do not want to use .PRECIOUS which could cause obscure build breakage. The targets specified as .SECONDARY must be explicit. $(targets) contains all targets that need to include .*.cmd files. So, the intermediates you want to keep are mostly in there. Therefore, mark $(targets) as .SECONDARY. It means primary targets are also marked as .SECONDARY, but I do not see any drawback for this. I replaced some .SECONDARY / .PRECIOUS markers with 'targets'. This will make Kbuild search for non-existing .*.cmd files, but this is not a noticeable performance issue. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Frank Rowand <frowand.list@gmail.com> Acked-by: Ingo Molnar <mingo@kernel.org>
2018-01-22sparc: vDSO: remove an extra tabDan Carpenter1-1/+1
This statement is indented one tab too far which is confusing and leads to a Smatch warning: arch/sparc/vdso/vma.c:254 arch_setup_additional_pages() warn: curly braces intended? Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-15vDSO for sparcNagarathnam Muthusamy13-0/+1265
Following patch is based on work done by Nick Alcock on 64-bit vDSO for sparc in Oracle linux. I have extended it to include support for 32-bit vDSO for sparc on 64-bit kernel. vDSO for sparc is based on the X86 implementation. This patch provides vDSO support for both 64-bit and 32-bit programs on 64-bit kernel. vDSO will be disabled on 32-bit linux kernel on sparc. *) vclock_gettime.c contains all the vdso functions. Since data page is mapped before the vdso code page, the pointer to data page is got by subracting offset from an address in the vdso code page. The return address stored in %i7 is used for this purpose. *) During compilation, both 32-bit and 64-bit vdso images are compiled and are converted into raw bytes by vdso2c program to be ready for mapping into the process. 32-bit images are compiled only if CONFIG_COMPAT is enabled. vdso2c generates two files vdso-image-64.c and vdso-image-32.c which contains the respective vDSO image in C structure. *) During vdso initialization, required number of vdso pages are allocated and raw bytes are copied into the pages. *) During every exec, these pages are mapped into the process through arch_setup_additional_pages and the location of mapping is passed on to the process through aux vector AT_SYSINFO_EHDR which is used by glibc. *) A new update_vsyscall routine for sparc is added to keep the data page in vdso updated. *) As vDSO cannot contain dynamically relocatable references, a new version of cpu_relax is added for the use of vDSO. This change also requires a putback to glibc to use vDSO. For testing, programs planning to try vDSO can be compiled against the generated vdso(64/32).so in the source. Testing: ======== [root@localhost ~]# cat vdso_test.c int main() { struct timespec tv_start, tv_end; struct timeval tv_tmp; int i; int count = 1 * 1000 * 10000; long long diff; clock_gettime(0, &tv_start); for (i = 0; i < count; i++) gettimeofday(&tv_tmp, NULL); clock_gettime(0, &tv_end); diff = (long long)(tv_end.tv_sec - tv_start.tv_sec)*(1*1000*1000*1000); diff += (tv_end.tv_nsec - tv_start.tv_nsec); printf("Start sec: %d\n", tv_start.tv_sec); printf("End sec : %d\n", tv_end.tv_sec); printf("%d cycles in %lld ns = %f ns/cycle\n", count, diff, (double)diff / (double)count); return 0; } [root@localhost ~]# cc vdso_test.c -o t32_without_fix -m32 -lrt [root@localhost ~]# ./t32_without_fix Start sec: 1502396130 End sec : 1502396140 10000000 cycles in 9565148528 ns = 956.514853 ns/cycle [root@localhost ~]# cc vdso_test.c -o t32_with_fix -m32 ./vdso32.so.dbg [root@localhost ~]# ./t32_with_fix Start sec: 1502396168 End sec : 1502396169 10000000 cycles in 798141262 ns = 79.814126 ns/cycle [root@localhost ~]# cc vdso_test.c -o t64_without_fix -m64 -lrt [root@localhost ~]# ./t64_without_fix Start sec: 1502396208 End sec : 1502396218 10000000 cycles in 9846091800 ns = 984.609180 ns/cycle [root@localhost ~]# cc vdso_test.c -o t64_with_fix -m64 ./vdso64.so.dbg [root@localhost ~]# ./t64_with_fix Start sec: 1502396257 End sec : 1502396257 10000000 cycles in 380984048 ns = 38.098405 ns/cycle V1 to V2 Changes: ================= Added hot patching code to switch the read stick instruction to read tick instruction based on the hardware. V2 to V3 Changes: ================= Merged latest changes from sparc-next and moved the initialization of clocksource_tick.archdata.vclock_mode to time_init_early. Disabled queued spinlock and rwlock configuration when simulating 32-bit config to compile 32-bit VDSO. V3 to V4 Changes: ================= Hardcoded the page size as 8192 in linker script for both 64-bit and 32-bit binaries. Removed unused variables in vdso2c.h. Added -mv8plus flag to Makefile to prevent the generation of relocation entries for __lshrdi3 in 32-bit vdso binary. Signed-off-by: Nick Alcock <nick.alcock@oracle.com> Signed-off-by: Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com> Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>