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authorVineet Gupta <vgupta@synopsys.com>2020-10-22 03:16:22 -0700
committerVineet Gupta <vgupta@synopsys.com>2020-10-22 10:57:58 -0700
commit8c42a5c02bec6c7eccf08957be3c6c8fccf9790b (patch)
treebaaec812df674806c3e7e1f6ce5e3e4534a5b997 /arch/alpha/kernel
parent6364d1b41cc382db3b03cf33c57b6007ee8f09cf (diff)
downloadlinux-stericsson-8c42a5c02bec6c7eccf08957be3c6c8fccf9790b.tar.gz
ARC: perf: redo the pct irq missing in device-tree handling
commit feb92d7d3813456c11dce21 "(ARC: perf: don't bail setup if pct irq missing in device-tree)" introduced a silly brown-paper bag bug: The assignment and comparison in an if statement were not bracketed correctly leaving the order of evaluation undefined. | | if (has_interrupts && (irq = platform_get_irq(pdev, 0) >= 0)) { | ^^^ ^^^^ And given such a chance, the compiler will bite you hard, fully entitled to generating this piece of beauty: | | # if (has_interrupts && (irq = platform_get_irq(pdev, 0) >= 0)) { | | bl.d @platform_get_irq <-- irq returned in r0 | | setge r2, r0, 0 <-- r2 is bool 1 or 0 if irq >= 0 true/false | brlt.d r0, 0, @.L114 | | st_s r2,[sp] <-- irq saved is bool 1 or 0, not actual return val | st 1,[r3,160] # arc_pmu.18_29->irq <-- drops bool and assumes 1 | | # return __request_percpu_irq(irq, handler, 0, | | bl.d @__request_percpu_irq; | mov_s r0,1 <-- drops even bool and assumes 1 which fails With the snafu fixed, everything is as expected. | bl.d @platform_get_irq <-- returns irq in r0 | | mov_s r2,r0 | brlt.d r2, 0, @.L112 | | st_s r0,[sp] <-- irq isaved is actual return value above | st r0,[r13,160] #arc_pmu.18_27->irq | | bl.d @__request_percpu_irq <-- r0 unchanged so actual irq returned | add r4,r4,r12 #, tmp363, __ptr Cc: <stable@vger.kernel.org> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/alpha/kernel')
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