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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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d6ab9fc745
Before this patch, the TOC code used a pre-allocated stack of 16kb for each possible CPU. That space overhead was the reason why the TOC feature wasn't enabled by default for 32-bit kernels. This patch rewrites the TOC code to use a per-cpu stack. That way we use much less memory now and as such we enable the TOC feature by default on all kernels. Additionally the dump of the registers and the stacktrace wasn't serialized, which led to multiple CPUs printing the stack backtrace at once which rendered the output unreadable. Now the backtraces are nicely serialized by a lock. Signed-off-by: Helge Deller <deller@gmx.de>
75 lines
1.4 KiB
ArmAsm
75 lines
1.4 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/* TOC (Transfer of Control) handler. */
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.level 1.1
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#include <asm/assembly.h>
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#include <linux/threads.h>
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#include <linux/linkage.h>
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.text
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.import toc_intr,code
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.import toc_stack,data
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.align 16
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ENTRY_CFI(toc_handler)
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load32 PA(toc_stack),%sp
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#ifdef CONFIG_SMP
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/* get per-cpu toc_stack address. */
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mfctl %cr30, %r1
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tophys %r1,%r2 /* task_struct */
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LDREG TASK_TI_CPU(%r2),%r4 /* cpu */
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load32 PA(__per_cpu_offset),%r1
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LDREGX %r4(%r1),%r4
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add %r4,%sp,%sp
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#endif
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/*
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* setup pt_regs on stack and save the
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* floating point registers. PIM_TOC doesn't
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* save fp registers, so we're doing it here.
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*/
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copy %sp,%arg0
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ldo PT_SZ_ALGN(%sp), %sp
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/* clear pt_regs */
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copy %arg0,%r1
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0: cmpb,<<,n %r1,%sp,0b
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stw,ma %r0,4(%r1)
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ldo PT_FR0(%arg0),%r25
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save_fp %r25
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/* go virtual */
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load32 PA(swapper_pg_dir),%r4
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mtctl %r4,%cr24
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mtctl %r4,%cr25
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/* Clear sr4-sr7 */
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mtsp %r0, %sr4
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mtsp %r0, %sr5
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mtsp %r0, %sr6
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mtsp %r0, %sr7
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tovirt_r1 %sp
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tovirt_r1 %arg0
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virt_map
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loadgp
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#ifdef CONFIG_64BIT
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ldo -16(%sp),%r29
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#endif
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load32 toc_intr,%r1
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be 0(%sr7,%r1)
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nop
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ENDPROC_CFI(toc_handler)
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/*
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* keep this checksum here, as it is part of the toc_handler
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* spanned by toc_handler_size (all words in toc_handler are
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* added in PDC and the sum must equal to zero.
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*/
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SYM_DATA(toc_handler_csum, .long 0)
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SYM_DATA(toc_handler_size, .long . - toc_handler)
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