/* * (C) 2004 Bruno Ducrot * * Licensed under the terms of the GNU GPL License version 2. * * Based on code found in * linux/arch/i386/kernel/cpu/cpufreq/powernow-k8.c * and originally developed by Paul Devriendt */ #include #include #include #include #include #include #include #include #define MCPU 32 #define MSR_FIDVID_STATUS 0xc0010042 #define MSR_S_HI_CURRENT_VID 0x0000001f #define MSR_S_LO_CURRENT_FID 0x0000003f static int get_fidvid(uint32_t cpu, uint32_t *fid, uint32_t *vid) { int err = 1; uint64_t msr = 0; int fd; char file[20]; if (cpu > MCPU) goto out; sprintf(file, "/dev/cpu/%d/msr", cpu); fd = open(file, O_RDONLY); if (fd < 0) goto out; lseek(fd, MSR_FIDVID_STATUS, SEEK_CUR); if (read(fd, &msr, 8) != 8) goto err1; *fid = ((uint32_t )(msr & 0xffffffffull)) & MSR_S_LO_CURRENT_FID; *vid = ((uint32_t )(msr>>32 & 0xffffffffull)) & MSR_S_HI_CURRENT_VID; err = 0; err1: close(fd); out: return err; } /* Return a frequency in MHz, given an input fid */ static uint32_t find_freq_from_fid(uint32_t fid) { return 800 + (fid * 100); } /* Return a voltage in miliVolts, given an input vid */ static uint32_t find_millivolts_from_vid(uint32_t vid) { return 1550-vid*25; } int main (int argc, char *argv[]) { int err; int cpu; uint32_t fid, vid; if (argc < 2) cpu = 0; else cpu = strtoul(argv[1], NULL, 0); err = get_fidvid(cpu, &fid, &vid); if (err) { printf("can't get fid, vid from MSR\n"); printf("Possible trouble: you don't run a powernow-k8 capable cpu\n"); printf("or you are not root, or the msr driver is not present\n"); exit(1); } printf("cpu %d currently at %d MHz and %d mV\n", cpu, find_freq_from_fid(fid), find_millivolts_from_vid(vid)); return 0; } 726d27056081d0250c0e173e4b155aa340'>diff
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authorIago Abal <mail@iagoabal.eu>2017-01-11 14:00:21 +0100
committerVinod Koul <vinod.koul@intel.com>2017-01-25 15:35:11 +0530
commit91539eb1fda2d530d3b268eef542c5414e54bf1a (patch)
tree960f5ca6342ad20837aff18aad6e8ecd7da32fd6 /include/dt-bindings/clock/hi3519-clock.h
parent6610d0edf6dc7ee97e46ab3a538a565c79d26199 (diff)
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the following double-lock bug: Double lock: 1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236; 2. call to function `pl330_release_channel' immediately after; 3. call to function `dma_pl330_rqcb' in line 1753; 4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505. I have fixed it as suggested by Marek Szyprowski. First, I have replaced `pch->lock' with `pl330->lock' in functions `pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids the double-lock by acquiring a different lock than `dma_pl330_rqcb'. NOTE that, as a result, `pl330_free_chan_resources' executes `list_splice_tail_init' on `pch->work_list' under lock `pl330->lock', whereas in the rest of the code `pch->work_list' is protected by `pch->lock'. I don't know if this may cause race conditions. Similarly `pch->cyclic' is written by `pl330_alloc_chan_resources' under `pl330->lock' but read by `pl330_tx_submit' under `pch->lock'. Second, I have removed locking from `pl330_request_channel' and `pl330_release_channel' functions. Function `pl330_request_channel' is only called from `pl330_alloc_chan_resources', so the lock is already held. Function `pl330_release_channel' is called from `pl330_free_chan_resources', which already holds the lock, and from `pl330_del'. Function `pl330_del' is called in an error path of `pl330_probe' and at the end of `pl330_remove', but I assume that there cannot be concurrent accesses to the protected data at those points. Signed-off-by: Iago Abal <mail@iagoabal.eu> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'include/dt-bindings/clock/hi3519-clock.h')